Easter Offensive The Easter Offensive ( Chiến dịch Xuân hè 1972 in Vietnamese ) was a military campaign conducted by the People ' s Army of Vietnam ( PAVN ) against the Army of the Republic of Vietnam ( ARVN , the regular army of South Vietnam ) and the United States military between March 30 and October 22 , 1972 , during the Vietnam War . This conventional invasion ( the largest offensive operation since 300 , 000 Chinese volunteers had crossed the Yalu River into North Korea during the Korean War ) was a radical departure from previous North Vietnamese offensives . The offensive was not designed to win the war outright , but to gain as much territory and destroy as many units of the ARVN as possible , to improve the North ' s negotiating position as the Paris Peace Accords drew towards a conclusion . The US high command had been expecting an attack in 1972 , but the size and ferocity of the assault caught the defenders off balance because the attackers struck on three fronts simultaneously with the bulk of the North Vietnamese army . This first attempt by the Democratic Republic of Vietnam ( North Vietnam ) to invade the south since the Tet Offensive of 1968 became characterized by conventional infantry / armor assaults backed by heavy artillery , with both sides fielding the latest in technological advances in weapons systems . In the I Corps Tactical Zone , North Vietnamese forces overran South Vietnamese defensive positions in a month - long battle and captured Quảng Trị city before moving south in an attempt to seize Huế . PAVN similarly eliminated frontier defense forces in the II Corps Tactical Zone and advanced to seize the provincial capital of Kon Tum , which would have opened the way to the sea , splitting South Vietnam in two . Northeast of Saigon , in the III Corps Tactical Zone , PAV forces overran Loc Ninh and advanced to assault the capital of Bình Long Province at An Lộc . The campaign can be divided into three distinct phases : April was a month of PAV advances ; May became a period of equilibrium ; in June and July the South Vietnamese forces counterattacked , culminating in the recapture of Quảng Trị City in September . On all three fronts of the offensive , initial North Vietnamese successes were hampered by high casualties , inept tactics , and the increasing application of U . S . and South Vietnamese air power . One result of the offensive was the launching of Operation Linebacker II , the first sustained bombing of North Vietnam by the U . S . since November 1968 . Although South Vietnamese forces withstood their greatest trial thus far in the conflict , the North Vietnamese accomplished two important goals : they had gained valuable territory within South Vietnam from which to launch future offensives , and they had obtained a better bargaining position at the peace negotiations being conducted in Paris . Background . Planning . In the wake of the failed South Vietnamese Operation Lam Son 719 , the Hanoi leadership began discussing a possible offensive during the 19th Plenum of the Central Committee of the Lao Dong Party in early 1971 . By December , the Politburo had decided to launch a major offensive early in the following year . 1972 would be a U . S . presidential election year , and the possibility of affecting the outcome was enticing and there was increasing anti - war sentiment among the population and government of the U . S . With continuing American troop withdrawals , South Vietnamese forces were stretched to the breaking point along a border of more than , and the poor performance of ARVN troops in the offensive into Laos promised an easy victory . This decision marked the end of three years of political infighting between two factions within the Politburo : those members grouped around Truong Chinh , who favored following the Chinese model of continued low - intensity guerrilla warfare and rebuilding the north ; and the " southern firsters " centered around Defense Minister Vo Nguyen Giap and supported by First Party Secretary Le Duan ( both of whom supported the Soviet model of big offensives ) . The failure of the Tet Offensive of 1968 had led to a downgrading of Giap ' s influence during the ensuing years , but the victory achieved over South Vietnamese forces during the Laotian incursion brought Giap ' s strategy back into the ascendant . As a result , Le Duan was given responsibility for the key planning decisions for the operation , but Giap never rose to his former prominence , dealing chiefly with logistical matters and the approval of operational planning . The officer entrusted with the actual conduct of the offensive was the PAVN chief of staff , General Van Tien Dung . The central questions then became where and with what forces the offensive would be launched and what its goals were to be . Although North Vietnam had utilized the border regions of Laos and Cambodia as supply and manpower conduits for a decade and a half , it was quickly decided that the main thrust of the offensive would be launched across the Vietnamese Demilitarized Zone that separated the two Vietnams . There , the line of communication would be shortest and forces could be concentrated where " the enemy is weakest . . . violent attacks will disintegrate enemy forces . . . making it impossible for him to have enough troops to deploy elsewhere . " This was an important consideration , since the northern thrust would serve to divert South Vietnam ' s attention and resources while two other attacks were also to be launched : one into the central highlands in order to cut the country in two ; and another that would move east out of Cambodia to threaten Saigon . The offensive was given a title steeped in Vietnamese history . In 1773 , the three Tây Sơn brothers ( so - called because of the place of their origin ) united a Vietnam divided by civil war and social unrest . The youngest brother , Nguyễn Huệ , then defeated an invading Chinese army on the outskirts of Hanoi in 1788 . Although the campaign eventually employed the equivalent of 14 divisions , winning the war outright was not part of North Vietnam ' s game plan . The goals were much more limited . There was the distinct possibility of destroying or at least crippling large elements of the ARVN ; possibly deposing of South Vietnamese President Nguyễn Văn Thiệu ; convincing the U . S . as to the hopelessness of continued support to the South ; and demonstrating the failure of Vietnamization . The prospect of seizing a South Vietnamese provincial capital , which could then be proclaimed as the seat of the Provisional Revolutionary Government , was also enticing . The attitude of the North Vietnamese leadership was illustrated in an article in a 1972 party journal : " It doesn ' t matter whether the war is promptly ended or prolonged . . . Both are opportunities to sow the seeds ; all we have to do is to wait for the time to harvest the crop . " The northern leadership was taken aback during the summer of 1971 , when an announcement was made that U . S . President Richard M . Nixon would visit the People ' s Republic of China on a diplomatic mission before May 1972 . The Chinese placated the suspicions of their ally by reassuring North Vietnam that even more military and economic aid would be forthcoming in 1972 . The Soviet Union , perceiving the growing antagonism between the People ' s Republic and North Vietnam , sought to widen the rift by also agreeing to " additional aid without reimbursement " for North Vietnam ' s military forces . These agreements led to a flood of equipment and supplies necessary for a modern , conventional army . This included 400 T - 54 and Type 59 ( a Chinese version of the T - 54 ) medium and 200 PT - 76 light amphibious tanks , hundreds of anti - aircraft missiles , including the shoulder - fired , heat - seeking SA - 7 Strela ( called the Grail in the West ) , anti - tank missiles , including the wire - guided AT - 3 Sagger and heavy - caliber , long - range artillery . To man the new equipment , 25 , 000 North Vietnamese troops received specialized training abroad , 80 percent of them in the Soviet Union or Eastern Europe . Miscalculation . During late 1971 , U . S . and South Vietnamese intelligence estimates of communist intentions were mixed . An offensive was expected , but intelligence as to its timing , location , and size were confusing . The communists had mounted an offensive inside South Vietnam in 1968 , but it was conducted mainly by the southerners of the NLF , which had essentially been destroyed in the process . Without NLF support inside South Vietnam , a large - scale PAVN offensive was considered highly unlikely . A North Vietnamese thrust across the DMZ was also considered unlikely . Past infiltration and offensive operations had been conducted through and from Laotian and Cambodian territory , and besides , a DMZ offensive would be a blatant violation of the Geneva agreement that North Vietnam was adamant in defending . In December , intelligence began to firm up . PAVN units that had been supporting Khmer Rouge operations in Cambodia began returning to the border areas . In both Laos and Cambodia there was also an unusual expansion of infiltration . Within North Vietnam , there was a noticeable increase in military recruitment . In January , Defense Intelligence Agency officers briefed Secretary of Defense Melvin Laird , stating that PAVN would attack after the Tết holidays and that the offensive would make widespread use of armored forces . Laird was unconvinced , telling the United States Congress in late January that a large communist offensive " was not a serious possibility " . U . S . and South Vietnamese intelligence services had no clear consensus as to communist intentions . MACV , on the other hand , was suspicious . It sent several reconnaissance teams into the Mu Gia and Ban Karai pass areas , and they discovered a heavy buildup in PAVN forces and equipment . MACV then decided that the North Vietnamese were building up for an offensive in the central highlands and the northern provinces of South Vietnam . The brunt of any such attack would , however , have to be borne by South Vietnamese forces , since U . S . troop strength had been reduced to 69 , 000 troops , most of whom were in support roles , and that number was to be reduced to 27 , 000 by 30 November . The U . S . commander , General Creighton W . Abrams , was convinced an offensive was likely , if not imminent , but he was also convinced that the attack would begin during or near the Tet holidays at the beginning of the year . He notified Admiral Thomas Moorer , chairman of the Joint Chiefs of Staff that the North Vietnamese might attempt to " duplicate the effects of the 1968 offensive , perhaps by a limited operation aimed less at inflicting defeat on the battlefield than in influencing American public opinion . " The consensus at MACV , however , was that such an offensive would be launched against II Corps , in the Central Highlands . When the offensive did not occur , both he and his headquarters were ridiculed in the American press for crying wolf . The moment of crisis seemed to have passed , and , by the end of March , allied forces that had been standing in readiness were returned to pacification efforts . U . S . Ambassador , Ellsworth Bunker , left for Nepal while General Abrams went to Thailand to spend the Easter holiday with his family . The ARVN units upon which the initial might of the North Vietnamese was to fall included the 1st and 3rd Infantry Divisions in Quảng Trị and Thừa Thiên Provinces , and the 2nd Division , further south . This force was supplemented by two brigades of Marines ( the 147th and 258th ) , the 51st Infantry Regiment , the 1st Ranger Group , and Regional and Popular Forces – approximately 30 , 000 men . The units were , however , fixed in static defensive positions and lacked adequate mobile reserves . Bearing the initial brunt of the attack would be the 3rd Division , created in October 1971 and located in an arc of outposts near the DMZ to replace departing American troops . To create the new unit , the 1st Division ( arguably ARVN ' s best unit ) was stripped of its 2nd Regiment , and the 11th Armored Cavalry was brought up from the I Corps reserve . Both units were experienced , well - trained , equipped , and led . The 3rd Division ' s other two regiments , the 56th and 57th , however , were made up of recaptured deserters , men released from jail , and regional and provincial forces . It was led by cast - off officers and sergeants from other units . Like other ARVN units at this stage of the conflict , the division was suffering from a dearth of American advisors , who by then served only at regimental , brigade , and divisional headquarters . Because of the general belief that the North Vietnamese would not violate the sacrosanct boundary , the unit was stationed in the relatively " safe " area directly below the DMZ . The division was commanded by newly promoted Brigadier General Vu Van Giai , the former deputy commander of the 1st Division . The I Corps commander , Lieutenant General Hoang Xuan Lam was an officer who epitomized the indecisiveness and ineffectiveness of Saigon ' s command structure , as had been discovered all too blatantly during Operation " Lam Son 719 " . Lam concentrated on administrative matters and left tactical decisions to his subordinate commanders . Considering the circumstances , this was a workable solution , but only so long as his division commanders encountered no major difficulties . U . S . intelligence had been squabbling over a possible PAVN cross - DMZ attack during the months preceding the offensive . DIA analysts " cautiously " predicted such a contingency , while the CIA downplayed the possibility . The General Lam ' s American advisors agreed with his assessment that a blatant North Vietnamese violation of the Geneva Accord was unlikely . When the weekend of Easter 1972 arrived , General Giai had planned to rotate the operational areas of his 56th Regiment ( along the central DMZ ) with the 2nd Regiment ( around the artillery base at Camp Carroll in the west ) . Because of a truck shortage , however , the units were moved simultaneously and became hopelessly intermixed and disorganized . At 11 : 30 on 30 March , both unit ' s headquarters shut down their radios for the exchange of operational areas . With communications fragmented , its units entangled , and the weather bad enough to prevent aerial operations , the 3rd Division offered the massed PAVN forces to the north an irresistible target . Offensive . The offensive began at noon on 30 March 1972 , when an intense artillery barrage rained down on the northernmost ARVN outposts in Quảng Trị Province . Two PAVN divisions ( the 304th and 308th – approximately 30 , 000 troops ) supported by more than 100 tanks ( in 2 Regiments ) then rolled over the Demilitarized Zone to attack I Corps , the five northernmost provinces of South Vietnam . The North Vietnamese 308th Division and two independent regiments assaulted the " ring of steel " , the arc of ARVN firebases just south of the DMZ . From the west , the 334B PAVN Division , including an armoured regiment , moved out of Laos along Route 9 , past Khe Sanh , and into the Quảng Trị River Valley . Significantly , allied intelligence had failed to predict either the scale of the offensive or the method of attack , giving PAVN " the inestimable benefit of shock effect , a crucial psychological edge over defenders who had expected something quite different . " On 1 April , South Vietnamese General Giai , ordered a withdrawal of the 3rd Division south of the Cua Viet River in order for his troops to reorganize . The following morning , ARVN armoured elements held off a PAVN offensive briefly when the crucial Highway QL - 1 bridge over the Cue Viet River at Đông Hà was blown up by Capt . John Ripley , adviser to the 3rd Vietnamese Marine Battalion . The initial PAVN units were then joined by the 320B and 325C Divisions . Simultaneously , the 324B Division moved out of the A Shau Valley and advanced directly eastward toward Fire Bases Bastogne and Checkmate , which protected the old imperial capital of Huế from the west . The North Vietnamese advance had been timed to coincide with the seasonal monsoon , whose cloud ceilings negated many U . S . airstrikes . PAVN advance elements also soon followed by antiaircraft units armed with new ZSU - 57 - 2 tracked weapon platforms and man - portable , shoulder - fired Grail missiles , which made low - level bombing attacks hazardous . Camp Carroll , an artillery firebase halfway between the Laotian border and the coast , was the linchpin of the South Vietnamese northern and western defense line and was the strongest obstacle to the North Vietnamese before Quảng Trị City . On 2 April Colonel Pham Van Dinh , commander of the 56th ARVN Regiment , surrendered the camp and his 1 , 500 troops with barely a shot being fired . Later in the day , ARVN troops abandoned Mai Loc , the last western base . This allowed North Vietnamese forces to cross the Cam Lo bridge , 11 kilometers to the west of Dong Ha . PAVN then had almost unrestricted access to western Quảng Trị Province north of the Thach Han River . The PAVN advance was slowed by delaying actions for three weeks , and the South Vietnamese launched several counterattacks , but on the morning of 27 April , the North Vietnamese came on again , launching multi - pronged attacks against Dong Ha ( which fell on the following day ) and advancing to within 1 . 5 kilometers of Quảng Trị City . General Giai had planned a staged withdrawal from the city to consolidate south of the Thach Han , but bewildered by conflicting orders from Lam and Giai , most ARVN formations splintered and then collapsed , conceding most of the province north of the city . On 29 April , Giai ordered a general retreat to the My Chanh River , thirteen kilometers to the south . U . S . military advisors in Quảng Trị called for emergency helicopter extraction and , on 1 May 132 survivors were evacuated from Quảng Trị , including 80 U . S . soldiers . The exodus of ARVN forces was joined by tens of thousands of South Vietnamese civilians fleeing from the fighting . As the mass of humanity jostled and shoved its way south on Highway 1 , it presented an inviting target for North Vietnamese artillerists . They were soon joined by PAVN infantry , who moved by the flank to attack the column . ARVN units , with no leadership and all unit cohesion gone , could muster no defense . Meanwhile , to the west , Fire Support Bases Bastogne and Checkmate had fallen after staunch ARVN defense and massive B - 52 bomber strikes , which inflicted heavy casualties . On 21 April , Abrams notified the U . S . Secretary of Defense that In summary . . . the pressure is mounting and the battle has become brutal . . . the senior military leadership has begun to bend and in some cases to break . In adversity , it is losing its will and cannot be depended upon to take the measures necessary to stand and fight . Giai evacuated the last of his forces from Quảng Trị City , which fell to PAVN forces on 2 May . That same day General Lam was summoned to Saigon for a meeting with President Nguyễn Văn Thiệu . He was relieved of command of I Corps and replaced by Lieutenant General Ngo Quang Truong , commander of III Corps and one of the ablest ARVN generals . Truong ' s mission was to defend the old imperial capital of Huế , minimize further losses , and retake captured territory . Although saddled with raw troops and constantly countermanded by his superiors , General Giai had conducted a reasonably good defense . Even Truong pleaded his case with Thieu , wanting to keep Giai in command of the 3rd Division . It was in vain . Giai , who was to be made the scapegoat for the collapse , was tried for " desertion in the face of the enemy " , and sentenced to five years in prison . An Lộc . The initial wave of the offensive was followed on 5 April by a PAVN advance out of Cambodia into Bình Long Province , northeast of Saigon . Its targets were the towns and airfields at Loc Ninh , Quan Loi , and An Lộc . The possible initial goals of the offensive in III Corps remain unclear , but probably began as probes that , if successful , could be easily reinforced . The invasion was launched from Cambodian Base Area 708 by the B - 2 Front ' s 5th PAVN / NLF Division and 203rd Armoured Regiment , which advanced down Highway 9 toward the border outpost of Loc Ninh . There , the 2 , 000 men of the ARVN 9th Regiment and a battalion of Rangers beat back five separate infantry / armor assaults before collapsing under the attack on 7 April . The North Vietnamese then isolated the 25th ARVN Division in neighboring Tây Ninh Province by sending two regiments to attack its forward outposts . Sensing that the provincial capital of An Lộc would be the next target , the III Corps commander , Lieutenant General Nguyen Van Minh dispatched the 5th Division to hold the town . They were reinforced by two battalions of the Ranger Group ( on 7 April ) and by two additional infantry battalions ( on 10 and 11 April ) . The 21st Infantry Division , which had been stationed in the Mekong Delta , was rushed to Chon Thanh to join a regiment of the 9th Infantry Division as a relief force . All forces in the area were placed under the command of Brigadier General Le Van Hung , commander of the 5th Division . The move was fortuitous for the South Vietnamese , since communist forces were indeed proceeding eastward toward An Lộc . Simultaneously , the 7th PAVN Division bypassed the town and moved south along Highway 13 to block any relief effort launched from Chon Thanh . The communists had decided that An Lộc , with its close proximity to Saigon , would be proclaimed as the capital of the Provisional Revolutionary Government , but even if they had been able to seize the town , they would never have been able to hold it . American air power would have made such an eventuality impossible . By 13 April , An Lộc was surrounded and under a combined artillery , armored , and infantry attack by the 9th PAVN / NLF Division . North Vietnamese forces advanced on the town through a deluge rockets , bombs , and napalm delivered by U . S . and South Vietnamese aircraft supported by massed artillery , tank , and small arms fire . Inside the town , the contingent of U . S . advisors became essential to the defense , serving as a separate staff organizing fire and air support , logistics , and intelligence . Colonel William Miller , the senior U . S . advisor , was not happy with General Hung ' s continuous reluctance to launch counterattacks and his reliance on U . S . air power to defeat the North Vietnamese . His hesitation and lack of motivation prompted Miller to report that : " He is tired – unstable – irrational – irritable – inadvisable – and unapproachable . " The communist attacks persisted and PAVN forces eventually battered their way into the town , seizing the airfield and reducing the ARVN perimeter to about a square kilometer . During another assault on the 21st , PAVN tanks actually forced their way through the defense perimeter but were held at bay and then destroyed by anti - tank weapons and helicopter gunships . North Vietnamese infantry did , however , manage to seize most of the northern sector of the town , where they began digging in ( often right across the street from the ARVN defenders ) . The initial shock of ARVN troops instilled by North Vietnamese armor was soon abated when they discovered that , because the supporting infantry failed to advance with the tanks , they became easy prey for anti - tank weapons . On other occasions , the opposite would occur , with massed infantry assaults moving forward without armored support . This failure of tactical coordination was one of PAVN ' s prime weaknesses during the offensive , and one that the allies were quick to exploit . As a result of his failure to seize the town quickly , the commander of the 9th Division was officially reprimanded and local command was handed over the senior officer of the 5th PAVN / NLF Division . Besides the lack of coordination , the major difficulty for the North Vietnamese was the rain of ordnance delivered upon them by incessant air strikes , which further reduced manpower and made resupply difficult . After the failure of the assault on 21 April , the battle devolved into a siege , with the North Vietnamese pounding An Lộc and its defenders with 1 , 200 to 2 , 000 mortar , rocket , and artillery rounds per day . An Lộc was completely surrounded and could only be resupplied by air , a situation made more difficult by the loss of the airfield . Resupply was accomplished , however , by 448 aerial missions which managed to deliver 2 , 693 tons of air - dropped food , medical supplies , and ammunition , supported by the US Army ' s " 549th QM ( AD ) " ( QuarterMaster , Air Delivery ) Rigger Company , which had been rapid - deployed from Okinawa in early April . From 22 April to 10 May , the tactical situation remained stable at what the " Paris Match " was calling " a Verdun or a Stalingrad " in III Corps . On the morning of 11 May , another North Vietnamese assault was launched after being preceded by an artillery bombardment that fired over 8 , 300 shells into a defense perimeter that had shrunk to a mere 1 , 000 by 1 , 500 yards before the day was over . PAVN forces again forced their way into An Lộc , but the effort collapsed in the face of tremendous aerial attack , which cost the North Vietnamese 40 tanks and over 800 men . The reasons for the failure were not hard to discern . Beginning at 05 : 30 that morning and continuing for the next 25 hours , the U . S . Air Force delivered a B - 52 strike every 55 minutes to support the defense . For the next three days , each time PAVN troops assembled to resume the attack , they were bombed in their assembly areas . A relief effort had been launched by the 21st ARVN Division , but it never arrived at An Lộc . For three weeks the division crept northward along Highway 13 but it was held up by constant delaying actions by smaller PAVN forces . Although the division never reached its goal , it may have inadvertently saved the beleaguered city by eventually diverting almost all of the elements of the 7th PAVN Division from the fighting . The climactic attack on An Lộc was launched on 14 May , when the North Vietnamese attacked directly into the teeth of the ARVN defense . The failed assault was described by Colonel Walt Ulmer , the 5th Division ' s senior advisor : " they were simply trying to pile on and pile on and pile on . They frittered away an awful lot of manpower . " Northern collapse . Although North Vietnamese forces remained in the area and continued to shell An Lộc heavily , the impetus of their offensive was over . By 12 June , the last PAVN forces were driven from the city and its environs and over 1 , 000 ARVN wounded were evacuated . Slowly , the decimated North Vietnamese units faded away to the north and west as others covered their withdrawal . On 18 June , the headquarters of III Corps declared the siege to be over . The Saigon government claimed that 8 , 000 South Vietnamese had been killed or wounded at An Lộc , approximately 1 , 000 of whom were civilians . American sources claimed that 25 , 000 PAVN or NLF troops had been killed or wounded during the action , although those numbers could never be confirmed . Kon Tum . The objective PAVN forces during the third phase of the " Nguyen Hue Offensive " was to seize the cities of Kon Tum and Pleiku , thereby overrunning the Central Highlands . This would then open the possibility of proceeding east to the coastal plains , splitting South Vietnam in two . The highlands offensive was preceded by NLF diversionary operations that opened on 5 April in coastal Bình Định Province , which aimed at closing Highway 1 , seizing several ARVN firebases , and diverting South Vietnamese forces from operations further west . North Vietnamese forces , under the command of Lieutenant General Hoang Minh Thao , commander of the B - 3 Front , included the 320th and 2nd PAVN Divisions in the highlands and the 3rd PAVN Division in the lowlands – approximately 50 , 000 men . Arrayed against them in II Corps were the ARVN 22nd and 23rd Divisions , two armored cavalry squadrons , and the 2nd Airborne Brigade , all under the command of Lieutenant General Ngo Dzu . It had become evident as early as January that the North Vietnamese were building up for offensive operations in the tri - border region and numerous B - 52 strikes had been conducted in the area in hopes of slowing the build - up . ARVN forces had also been deployed forward toward the border in order to slow the PAVN advance and allow the application of airpower to deplete North Vietnamese manpower and logistics . The Bình Định offensive , however , threw General Dzu into a panic and almost convinced him to fall for the North Vietnamese ploy and divert his forces from the highlands . John Paul Vann , director of the U . S . Second Regional Assistance Group , reassured Dzu that it was only a ruse and to remain ready for the main blow , which he was convinced would come from western Laos . John Vann , although a civilian , had been granted the unique authority to command all U . S . military advisors within his region . Vann worked day and night , using his extensive civilian and military contacts to channel U . S . support ( especially air support ) to the region . Major General John Hill , Dzu ' s senior military advisor , described Vann ' s extraordinary actions : " The rest of us organized around Vann ' s personal efforts and concentrated on getting the resources marshalled to take advantage of the leadership he was exerting with the Vietnamese . " To counter the possible threat from the west , Dzu had deployed two regiments of the 22nd Division to Tan Canh and Dak To II and two armored squadrons to Ben Het . On 12 April , the 2nd PAVN Division , elements of the 203rd Tank Regiment , and several independent regiments of the B - 3 Front attacked the outpost at Tan Canh and the nearby firebase at Dak To . When the ARVN armor moved out of Ben Het toward Dak To II , it was ambushed and destroyed . The overwhelmed South Vietnamese defense northwest of Kon Tum quickly disintegrated , placing the command of III Corps in a quandary . With the rest of the 22nd Division covering the coast there were few forces left to defend the provincial capital of Kon Tum . The North Vietnamese southern advance inexplicably halted for three crucial weeks . While the northern crisis waned , however , General Dzu began to unravel , finding it increasingly difficult to make decisions . Vann gave up all pretext of South Vietnamese command , took over himself , and openly issued orders . He placed responsibility for the defense of the city of Kon Tum on the shoulders of Ly Tong Ba , commander of the 23rd Division . Vann then used massive B - 52 strikes to hold the North Vietnamese at arm ' s length and reduce their numbers while he managed to find additional troops with which to stabilize the situation . By 14 May , North Vietnamese forces had reached Kon Tum and launched their main assault . The 320th PAVN Division , the 1st and 141st Regiments of the 2nd PAVN Division , and elements of the 203rd Tank Regiment attacked the city from the north , south , and west . By the time of the assault , the city mustered a defensive force that consisted of the 23rd Division and several Ranger groups . Their three - week delay cost the North Vietnamese dearly . By 14 May , the worst of the fighting in I and II Corps was over and a majority of the B - 52s were free to concentrate on the Central Highlands . During the North Vietnamese attack , the positions of the 44th and 45th ARVN Regiments crumbled and were overrun , but a well - placed B - 52 strike landed directly on the PAVN attackers at the point of the breakthrough . The next morning , when the South Vietnamese returned to their former positions unopposed , 400 bodies were discovered , along with seven destroyed tanks . At Vann ' s insistence , a personnel shake - up took place in III Corps when President Thieu replaced Dzu with Major General Nguyen Van Toan , whose outwardly confident and assertive nature was the complete opposite of Dzu ' s . The actions at Kon Tum for the following two weeks became characterized by massed PAVN assaults that were lashed by B - 52 , tactical air , and helicopter gunship attacks . ARVN troops then counterattacked over the remains of the attacking wave . On 26 May , four North Vietnamese regiments supported by armored forces managed to punch a hole in the defense , but their advance was halted by U . S . helicopters firing new , tube - launched , optically tracked , wire - guided ( TOW ) missiles . During the following three days of fighting , 24 North Vietnamese T - 54 tanks were destroyed by TOWs and the breach was sealed . With the aid of the U . S . and South Vietnamese air forces and despite severe losses , ARVN managed to hold Kon Tum during the remainder of the battle . Aerial resupply was supported by the US Army ' s " 549th QM ( AD ) " ( QuarterMaster , Air Delivery ) Rigger Company , which had been rapid - deployed from Okinawa in early April . By early June , the North Vietnamese faded back to the west , leaving behind over 4 , 000 dead on the battlefield . It was estimated by U . S . intelligence that total PAVN casualties in the Central Highlands during the offensive totaled between 20 , 000 and 40 , 000 troops . John Vann did not have time to savor his victory . While returning to Kon Tum from a briefing in Saigon on 9 June , he was killed in a helicopter crash . Air support , " Freedom Train " , and " Linebacker " . The North Vietnamese had timed their offensive well by having it coincide with the end of the annual winter monsoon when low cloud cover and rain provided a blanket under which the offensive could proceed without interference by allied aerial attack . Air strikes were possible only by all - weather fighters or bombers , which could deliver their ordnance accurately through the cloud cover by radar direction or LORAN . These missions were conducted by aircraft assigned to the U . S . Seventh Air Force and Seventh / Thirteenth Air Force in South Vietnam and Thailand or by the U . S . Navy ' s Task Force 77 , offshore in the South China Sea . Besides the weather the most serious problem facing the Americans was that the drawdown of U . S . forces during the previous four years had included valuable ground support aircraft and their maintenance crews . By the spring of 1972 , the U . S . Air Force had only three squadrons of F - 4 Phantom s and one of A - 37 Dragonfly s available in the Republic of Vietnam , a total of 76 aircraft . Another 114 fighter - bombers were stationed at various bases in Thailand . 83 B - 52 Stratofortress heavy bombers were located at U - Tapao RTAFB and at Andersen Air Force Base , Guam . Task Force 77 had four carriers assigned to it , but only two , and were on station at the onset of the offensive . Their air wings totaled 140 strike aircraft . To rectify the aircraft shortage , from 7 April to 13 May 176 F - 4s and 12 F - 105 Thunderchief s were transferred from air bases in the Republic of Korea and the continental U . S . to Thailand during Operation " Constant Guard " I - IV . Between 5 February and 23 May , the Strategic Air Command ( SAC ) reinforced Guam during Operation " Bullet Shot " with a further 124 bombers , bringing the total available in - theater to 209 . The Seventh Fleet was also beefed up by the addition of four aircraft carrier groups , including those of the , , , and . This made four carriers available at any one time to conduct aerial operations . The South Vietnamese Air Force ( VNAF ) at this time consisted of nine squadrons of A - 1 Skyraider s , A - 37s , and F - 5 Freedom Fighter s , a total of 119 strike aircraft . There were also two squadrons of AC - 47 or AC - 119 fixed - wing gunships , totaling of 28 aircraft . The weather conditions made early ground support haphazard , and these difficulties were compounded by North Vietnamese anti - aircraft units , which advanced behind the front line elements . PAVN moved 85 and 100 mm radar - directed batteries south of the DMZ and , on 17 February , 81 SA - 2 Guideline missiles were launched from the DMZ area , downing three F - 4s . This heralded the farthest southern advance of SA - 2 units thus far during the conflict . This classic high - low anti - aircraft coverage made aerial attacks extremely hazardous , especially when it was enhanced by the new shoulder - fired Grail . The loss of the northern firebases early in the offensive in I Corps made U . S . naval gunfire the primary source of artillery support in that area . U . S . Marine Corps gunfire observers were then assigned to fly with forward air controllers , providing coordinates for shore targets . At the height of the offensive three U . S . cruisers and 38 destroyers were providing naval gunfire support . With clearing weather the number of aircraft sorties soared . Between April and June there were 18 , 000 combat sorties flown to support the ARVN defense , 45 percent by the U . S . Air Force , 30 percent by the Navy and Marine Corps , and 25 percent by the VNAF . B - 52s flew an additional 2 , 724 sorties . Ten U . S . and six VNAF aircraft were lost to SAM or anti - aircraft fire . On 4 April , reacting to the fierceness of the offensive , President Nixon authorized tactical airstrikes from the DMZ north to the 18th parallel , the southern panhandle of North Vietnam . This supply interdiction effort was the first systematic bombing carried out in North Vietnam proper since the end of Operation Rolling Thunder in November , 1968 . Airstrikes north of the 20th parallel were authorized on 5 April under the cover name Operation " Freedom Train " . The first B - 52 strike of the new operation was conducted on 10 April . President Nixon then decided to up the ante by targeting Hanoi and Haiphong . Between 1 May and 30 June , B - 52s , fighter - bombers , and fixed - wing gunships had carried out 18 , 000 sorties over North Vietnam and suffered 29 aircraft losses . On 8 May Nixon authorized the launching of Operation Pocket Money , the aerial mining of Haiphong and other North Vietnamese ports . Nixon had taken a gamble that Soviet Union , with which he was conducting negotiations for a strategic arms limitation treaty ( SALT I ) , would withhold a negative reaction in return for improved relations with the West . He was correct . The People ' s Republic of China also muted any overt response to the escalatory measures for the same reason . Emboldened , Nixon decided to launch Operation " Linebacker " a systematic aerial assault on North Vietnam ' s transportation , storage , and air defense systems on 10 May . During " Linebacker " , the U . S . Air Force , Navy , and Marine Corps lost 134 aircraft while their North Vietnamese opponents lost 54 . Huế and the counteroffensive . Hoping to break the stalemate that was developing on the northern front , Lieutenant General Tran Van Quang , commander of the B - 4 Front , attacked west from the A Shau Valley toward Huế with the 324B Division . Spoiling attacks by the 1st ARVN Division , however , threw off the timetable . On 28 April 29 and 803rd PAVN Regiments seized Firebase Bastogne , the strongest anchor on Huế ' s western flank . This made Firebase Checkmate untenable , and it too was evacuated that night . This exposed Huế to a direct thrust along Route 547 . On 2 May PAVN forces south of Huế tried to surround the city . The North Vietnamese also attempted to press their attack southward down Highway 1 and across the Thach Han to Huế , but , fortunately for the South Vietnamese , after Truong took command , the 1st and Marine Divisions were reinforced by the 2nd and 3rd Brigades of the Airborne Division ( which now totaled three brigades ) , and the reorganized 1st Ranger Group , raising the ARVN manpower total to 35 , 000 . Also fortuitous was a one - week clearing of the weather , which allowed the application of massive U . S . bombing . The North Vietnamese advance was halted on 5 May . By mid - May , Truong felt strong enough to go on the offensive in a series of limited attacks , feints , and raids codenamed " Song Than " ( Tidal Wave ) that were planned to throw the North Vietnamese off balance , enlarge the defensive perimeter around Huế , and deny the enemy time and space to maneuver . Between 15 and 20 May , Firebases Bastogne and Checkmate were recaptured . PAVN forces then launched another attempt to take the city on 21 May , losing 18 tanks and approximately 800 men in the process . On 25 May a second North Vietnamese assault managed to cross the river , but ARVN defenders put up ferocious resistance , forcing their enemy back across on 29 May . This was the last serious assault on the defenses of Huế . Major General Frederick J . Kroesen , senior U . S . advisor in I Corps , believed that the fall of Quảng Trị should have heralded the fall of Huế , but the North Vietnamese did not exploit their opportunity quickly enough . " That he failed completely to take advantage of the moment must be classed as another great blunder of the Quảng Trị campaign . " By mid - June , clearing weather allowed more accurate aerial bombardment and shelling from U . S . warships offshore . On the 14th , Truong briefed President Thieu and MACV on his planned counterattack to retake Quảng Trị Province . Thieu was not convinced , preferring a smaller - scale operation . The persistent Truong finally convinced the president , emphasizing that such an effort would be possible " employing the superior firepower of our American ally . " Thieu finally approved the concept . Truong launched Operation " Lam Son 72 " on 28 June . The 1st Division continued its westward push toward Laos while the Airborne and Marine Divisions , the 1st Ranger Group , and the 7th Armored Cavalry moved north to retake Quảng Trị . The Airborne Division led the way and , utilizing airmobile end - runs and the North Vietnamese were slowly levered out of their defensive positions . The division then advanced to the outskirts of Quảng Trị City within ten days , but then President Thieu intervened in the operation . Truong had planned to bypass the city and push on quickly to the Cua Viet River , thereby isolating any PAVN defenders . Thieu , however , now demanded that Quảng Trị be taken immediately , seeing the city as " a symbol and a challenge " to his authority . It was not going to be an easy task for General Truong . The ARVN assault bogged down in the outskirts and the North Vietnamese , appraised of the plans for the offensive , moved the 304th and 208th Divisions to the west to avoid the U . S . airpower that was about to be unleashed upon Quảng Trị . The defense of the city and its walled citadel was left to PAVN replacement units and militia . Recalled one participant : " The new recruits came in at dusk . They were dead by dawn … No one had time to check where they were from , or who was their commander . " Others described the defense as a " senseless sacrifice " and referred to Quảng Trị as " Hamburger City " . On 11 July , the ARVN Marine Division launched a heli - borne assault north and east of the city which would cut the last remaining road and force the North Vietnamese to reinforce and resupply across the Thach Han River , making them vulnerable to air strikes . After a vicious , three - day battle against the 48th Regiment of the 320B PAVN Division , North Vietnamese forces broke and withdrew . During the month of July , American aircraft flew 5 , 461 tactical sorties and 2 , 054 B - 52 strikes to support the counteroffensive . On 27 July , the ARVN Marine Division was ordered to relieve the Airborne units as the lead element in the battle . But progress was slow , consisting of vicious house - to - house fighting and incessant artillery barrages by both sides . In September , the assault to capture the heavily - defended citadel was launched ; it was finally taken on 16 September . Truong ' s forces then advanced to the southern bank of the Thach Han River , where they halted , exhausted and depleted by heavy casualties and unable to push on to Dong Ha . Aftermath . At the conclusion of the ARVN counteroffensive , both sides were too exhausted to continue their efforts . Both sides , however , considered their efforts to have been successful . The South Vietnamese and Americans believed the policy of Vietnamization had been validated . The internal weaknesses of the South Vietnamese command structure , which had been rectified somewhat during the emergency , also reappeared once it had passed . During the operations , more than 25 , 000 South Vietnamese civilians had been killed and almost a million became refugees , 600 , 000 of whom were living in camps under government care . American casualties in combat for all of 1972 totaled only 300 killed , most of whom were killed during the offensive . Hanoi , which had committed 14 divisions and 26 independent regiments to the offensive ( virtually its entire army ) , had suffered approximately 100 , 000 casualties and almost all tanks destroyed ( 134 T - 54 s , 56 PT - 76 s and 60 T - 34 s ) . In return , it had gained permanent control of half of the four northernmost provinces — Quảng Trị , Thừa Thiên , Quảng Nam , and Quang Tin — as well as the western fringes of the II and III Corps sectors ( around 10 % of the country ) . The North Vietnamese leadership had made two grave miscalculations concerning the abilities of its enemies . The first was to underestimate the fighting ability of the ARVN , which by 1972 had become one of the best - equipped armies in the world ; the second was a failure to grasp the destructiveness of American air power unleashed against an enemy that was now fighting a conventional battle . Combined with these strategic errors , PAVN commanders had also thrown away their local numerical superiority by making repeated frontal attacks into heavy defensive fire , and suffered massive casualties as a consequence . Hanoi , however , wasted no time in making use of what it had gained . The North Vietnamese immediately began to extend their supply corridors from Laos and Cambodia into South Vietnam . The PAVN rapidly expanded port facilities at the captured town of Dong Ha , and within a year over 20 percent of the materiel destined for the southern battlefield was flowing across its docks . In Paris , the peace negotiations continued , but this time round , both sides were willing to make concessions . The chief American negotiator , Dr . Henry Kissinger , offered a cease - fire in place , recognition of the PRG by the Saigon government , and total American withdrawal from South Vietnam as incentives . These terms were actually enough to meet the criteria for victory that Hanoi ' s leaders had established before the offensive began . The only obstacle to a settlement then became Nguyễn Văn Thiệu , whose government would have to assent to any agreement . Due to Thieu ' s intransigence ( and his demand that the U . S . not abandon his nation after any agreement ) and new demands from Hanoi , the peace talks stalled in December . This led President Nixon to launch Operation Linebacker II , a bombing campaign aimed at North Vietnam ' s transportation network , especially around Hanoi and Haiphong . The Paris Peace Accords , signed in January 1973 , confirmed that North Vietnamese PAVN troops would remain in South Vietnam in the areas that they then occupied and had gained previously in the Easter Offensive .