Free Syrian Army operations During the Syrian civil war , numerous operations were conducted by the Free Syrian Army . Operations were modest following its formation in late July 2011 , but gradually expanded . The FSA would grow in size , to about 20 , 000 by December , and to an estimated 40 , 000 by June 2012 . By October , the FSA would start to receive military support from Turkey , who allowed the rebel army to operate its command and headquarters from the country ' s southern Hatay province close to the Syrian border , and its field command from inside Syria . The FSA would often launch attacks into Syria ’ s northern towns and cities , while using the Turkish side of the border as a safe zone and supply route . A year after its formation , the FSA would gain control over many towns close to the Turkish border . FSA fighters would periodically launch attacks across the border at Syria ' s northern edge . By September 2012 , the majority of Syria ' s northern frontier was under FSA control . As such , the FSA moved its command headquarters from southern Turkey to rebel - controlled territory of northern Syria , where it continued to launch operations against government - controlled towns and bases . The FSA conducted major operations other regions as well , including in and around the cities of Homs and Damascus . By December 2012 , the rebels had captured approximately 60 percent of Syria ' s territory . Armed action in 2011 . September . Battle of Rastan . From 27 September to 1 October , Syrian government forces , backed by tanks and helicopters , led a major offensive on the city of Rastan in Homs province , which had been under opposition control for a couple weeks . There were reports of large numbers of defections in the city , and the Free Syrian Army reported it had destroyed 17 armoured vehicles during clashes in Rastan , using RPGs and booby traps . A defected officer in the Syrian opposition claimed that over a hundred officers had defected as well as thousands of conscripts , although many had gone into hiding or home to their families , rather than fighting the loyalist forces . The Battle of Rastan between the government forces and the Free Syrian Army was the longest and most intense action up until that time . After a week of fighting , the FSA was forced to retreat from Rastan . To avoid government forces , the leader of the FSA , Col . Riad Asaad , retreated to the Turkish side of Syrian - Turkish border . October . Jabal al - Zawiya clashes . By the beginning of October , clashes between loyalist and defected army units were being reported fairly regularly . During the first week of the month , sustained clashes were reported in Jabal al - Zawiya in the mountainous regions of Idlib province . On 13 October , clashes were reported in the town of Haara in Daraa province in the south of Syria that resulted in the death of two rebel and six loyalist soldiers , according to the London based Syrian Observatory for Human Rights . Clashes were also reported in the city of Binnish in Idlib province with a total of 14 fatalities for both affected towns , including rebels , loyalists and civilians . A few days later on 17 October , five government troops were killed in the town of Qusair in the central province of Homs , near the border with Lebanon , and 17 people were reported wounded in skirmishes with defectors in the town of Hass in Idlib province near the mountain range of Jabal al - Zawiya , although it was unclear if the wounded included civilians . According to the London based organization , an estimated 11 government soldiers were killed that day , four of which were killed in a bombing . It was not clear if the defectors linked to these incidents were connected to the Free Syrian Army . Continuing clashes in Idlib province . On 20 October , the opposition reported that clashes occurred between loyalists and defectors in Burhaniya , near the town of Qusair in the central province of Homs , leading to the death of several soldiers and the destruction of two military vehicles . A week later on 25 October , clashes occurred in the northwestern town of Maarat al - Numaan in Idlib province between loyalists and defected soldiers at a roadblock on the edge of the town . The defectors launched an assault on the government held roadblock in retaliation for a raid on their positions the previous night . The next day on 26 October , the opposition reported that nine soldiers were killed by a rocket - propelled grenade when it hit their bus in the village of Hamrat , near the city of Hama . The gunmen who attacked the bus were believed to be defected soldiers . On 29 October , the opposition reported that 17 pro - Assad soldiers were killed in the city of Homs during fighting with suspected army deserters , including a defected senior official who was aiding the rebel soldiers . Two armoured personnel carriers were disabled in the fighting . Later the number of casualties was revised to 20 killed and 53 wounded soldiers in clashes with presumed army deserters , according to Agence France Presse . In a separate incident , 10 security agents and a deserter were killed in a bus ambush near the Turkish border , opposition activists reported . The Syrian Observatory of Human Rights reported that the bus was transporting security agents between the villages of Al - Habit and Kafrnabuda in Idlib province when it was ambushed " by armed men , probably deserters " . November . On 1 November , dozens of armored vehicles converged on a village in the Kafroma in Idlib , as defected soldiers killed an unknown number of Syrian soldiers . A few days later on 5 November , at least nine people died in clashes between soldiers , protesters and defectors , and four Shabeeha were killed in Idlib reportedly by army deserters . On the same day , the state - news agency SANA reported the deaths of 13 soldiers and policemen as a result of clashes with armed groups . According to SANA , four policemen were also wounded in clashes with an armed group in Kanakir in the Damascus countryside while one of the armed individuals died , additionally that day , two explosive devices were dismantled . Defections and checkpoint raids . More army defections were reported in Damascus on 10 November , three out of at least nine defectors were shot dead by loyalist gunmen after abandoning their posts . The same day , clashes reportedly resulted in the death of a fifteen year old boy in Khan Sheikhoun , when he was caught in crossfire between Assad loyalists and the free army . Also on the 10 November " at least four soldiers in the regular army were killed at dawn in an attack , headed by armed men – probably deserters – on a military checkpoint in Has region , near Maaret al - Numan town " according to the Syrian Observatory For Human Rights . However , the number has also been put at five soldiers . A checkpoint in Maarat al - Numaan three kilometers south of Homs also came under attack by defectors , resulting in an increase in tank deployment by Syrian security forces in the city . In November , there were conflicting reports of the number of Syrian soldiers injured and killed . On 11 November , Reuters reported that 26 soldiers were killed , while Syrian state media reported the lower figure of 20 soldiers killed at this time . For the month up until 13 November , the Local Coordination Committees reported the death of about 20 soldiers , the Syrian Observatory of Human Rights reported the death of more than 100 soldiers , and the Syrian state media SANA reported the death of 71 soldiers . Increased Clashes in Daraa province began on the 14 November when 34 soldiers and 12 defectors were killed in an ambush by the free army . The death toll as a result of the fighting also included 23 civilians . One day later on 15 November , eight soldiers and security forces troops were killed by an assault on a checkpoint in Hama province , according to activists . Damascus Intelligence complex attack . On 16 November , in a coordinated attack , an air force intelligence complex in the Damascus suburb of Harasta was attacked . According to the Free Syrian Army , they did so with machine guns and rocket - propelled grenades , leading to the death of at least six soldiers with twenty others wounded . A western diplomat said the assault was " hugely symbolic and tactically new " . The attack on the air force intelligence complex was a continuation of clashes in Damascus . The next day , the Free Syrian Army launched an assault against the Baath party youth headquarters in Idlib province with RPG ' s and small arms . The state news agency SANA reported the deaths of three Syrian troops as a result of a bomb blast , with an officer also critically wounded and two law - enforcement agents injured . Three members of the security forces were reportedly killed on between the 18 to 19 November by the Free Syrian Army . Multiple attacks on 19 December by armed groups were also reported by the state news agency SANA . State news also reported that ten wanted armed individuals were captured in Maarat al - Numan . According to Reuters , two rocket propelled grenades hit a Baath party building in Damascus on 20 December . This if true is highly significant ; it is the first attack of this kind within the capital itself and would lend weight to the Free Syrian Army ' s claim that it can strike anywhere in Syria . According to Reuters , a witness said : " Security police blocked off the square where the Baath ' s Damascus branch is located . But I saw smoke rising from the building and fire trucks around it . " The building was reportedly mostly empty in the attack which took place before dawn and was seemingly a message to the regime . However , an AFP reporter went to the area and saw no signs of the claimed attack while residents said that there had been no explosions . Colonel Asaad himself denied that the Free Syrian Army was responsible for the attack . It is therefore likely that it was a provocation by the Assad regime . On 22 November , the Free Syrian Army claimed responsibility for killing eight members of the security forces . On 23 November , five defected soldiers were killed ; four in a farm near Daraa where they were hiding and one near the Lebanese border , according to Reuters . If there was a confrontation between the soldiers and government troops is unclear . Any government troop casualties as a result of these clashes are also unknown . Homs airbase attack . According to the Syrian Observatory for Human Rights , on the 24 November soldiers and Shabiha with armoured vehicles started operations in farmland west of Rastan in Homs province to track down defectors . 24 people died as a result ( if they were soldiers , defectors or civilians was not stated ) . At least fifty tanks and other armoured vehicle opened fire with 50 cal . machine guns and anti - aircraft weapons on positions held by the Free Syrian Army on Rastan ' s outskirts . Deaths were also reported in Daraa and Homs On 24 November , 11 defectors were killed and four wounded during clashes on the western outskirts of Homs . In an attack on an airbase in Homs province on 25 November , six elite pilots , one technical officer and three other personnel were killed . The Syrian government vowed to " cut every evil hand " of the attackers as a result . On that same day , at least 10 troops and security service agents were killed in clashes with mutinous soldiers in the east of Syria . The Syrian Observatory for Human Rights said the deaths occurred in Deir Ezzor , while early the next day a civilian was also killed in the eastern city . Several defectors were also killed or wounded . Army convoy ambushes . Sustained clashes in Idlib province began on 26 November between loyalist and opposition fighters . At least 8 soldiers were killed and 40 more wounded that day when the free army attacked them in Idlib , the Syrian Observatory for Human Rights reported . " A group of deserters attacked a squad of soldiers and security agents in a convoy of seven vehicles , including three all - terrain vehicles , on the road from Ghadka to Maarat al - Numaan ” , the Britain - based watchdog said . “ Eight were killed and at least 40 more were wounded . The deserters were able to withdraw without suffering any casualties , ” it added . The FSA claimed to be behind the attack . Syrian human rights activists claimed that the Free Syrian Army had killed three loyalist soldiers and captured two others on 29 November , although they did not specify where . According to the Syrian Observatory for Human Rights , seven soldiers were killed on 30 November in fighting in the town of Deal in Daraa province after security forces moved on the town in force . The fighting went on from the early morning to the late afternoon . " Two security force vehicles were blown up . Seven ( troops ) were killed , " said Rami Abdel Rahman , head of the observatory . An activist from the town , in the province of Daraa , said some 30 busloads of security men stormed Deal and two of the buses were blown up in fighting " between security forces and defectors , " the Observatory reported . One of the destroyed buses was allegedly empty . December . Idlib intelligence building raid . On 1 December , FSA troops launched a raid on an intelligence building in Idlib , leading to a three - hour firefight in which eight loyalists were killed . This came the same day the United Nations announced it considered Syria to be in a state of civil war . On 3 December , clashes in the city of Idlib in the north of Syria the next day resulted in the death of seven Assad loyalist soldiers , five defectors and three civilians . On 4 December , heavy fighting raged in Homs during which at least five FSA insurgents were killed and one wounded . Defected soldiers killed four members of the security forces , including an officer , at the southern city of Deal in Daraa province on 5 December . On 7 December , there were clashes between the Syrian regular army and groups of army defectors near the radio broadcasting centre in the town of Saraqeb , in Idib district . An armoured personnel carrier ( APC ) of the regular army was destroyed during the clashes . Meanwhile , joint security and military forces raided the houses at the edges of Saraqeb and arrested three activists , at dawn time . This was according to the Syrian Observatory for Human Rights . Between 1 December and 7 December , the Syrian state news agency SANA reported the deaths of 48 members of the state security forces . Escalating clashes in Daraa . A military tank was destroyed in Homs on 9 December . Four defected soldiers also apparently died in fighting on 9 December . On 10 December , activists say clashes between Syrian troops and army defectors killed at least two people . The British - based Syrian Observatory for Human Rights says two army armoured carriers were burned in the pre - dawn clash in the northwestern town of Kfar Takharim . On 11 December , it was reported that a battle was fought between defectors and the Syrian army in Busra al - Harir and Lujah . Troops , mainly from the 12th Armoured Brigade , based in Isra , 40 km from the border with Jordan , stormed the nearby town of Busra al - Harir , the Reuters news agency reported . It was apparently the largest battle to take place in the conflict so far . At least five soldiers , including a military officer , are reported to have been killed the same day in an unspecified location . In one of Sunday ’ s clashes , which took place before dawn in the northwestern town of Kfar Takharim , two of the military ’ s armored vehicles were set ablaze , said the British - based Syrian Observatory for Human Rights . Three other vehicles were burned in another clash near the southern village of Busra al - Harir , the group said . Similar battles took place in several other parts of the south , said the Observatory and another activist group called the Local Coordination Committees . Urban fighting in Homs . Syrian army defectors , who operate under the banner of the Free Syrian Army , say that a senior army officer was killed on 11 December after refusing to fire on civilians in Homs . Maher al - Nueimi , a spokesman for the FSA , said that Brigadier - General Salman al - Awaja was given instructions to fire on residents of al - Quseir in Homs . When he refused , Nueimi said , he was killed . The FSA says that a large number of defections took place after the killing , as clashes broke out between al - Awaja ' s supporters in the army and the other soldiers who killed him . The Observatory said two people were killed in the clash with defectors in Kfar Takharim and two armoured vehicles were destroyed . On 12 December , three civilians and two defectors were killed during clashes in Idlib province . Fighting in Ebita , in the northwestern province of Idlib , continued throughout the night and into the early hours on 12 December . At least one fighter was killed and another injured in the assault . The FSA killed ten troops in an ambush on a convoy in Idlib , according to the Syrian Observatory for Human Rights . This attack was allegedly done to avenge the deaths of 11 civilians previously killed . A Syrian officer was also killed in a revenge attack . Loyalist soldiers reportedly fired upon a civilian car near Homs on 14 December , killing five people , in response , the Free Syrian Army staged an ambush against a loyalist convoy consisting of four jeeps , killing eight soldiers . The same day , three anti - regime military defectors were wounded in clashes with Syrian security forces in the village of Hirak in Daraa province . The FSA engaged loyalist army units and security service agents south of Damascus on 15 December , leading to 27 loyalist deaths and an unknown number of FSA casualties . The clashes broke out at three separate checkpoints in Daraa province around dawn Between 8 December and 15 December , the Syrian state news agency SANA reported the deaths of 68 members of the state security forces . A lieutenant colonel of the FSA was killed by the Syrian army on 17 December according to Local Committee , and opposition source . Unsuccessful defection in Idlib . On 19 December , the FSA suffered its largest loss of life when new defectors tried to abandon their positions and bases between the villages of Kensafra and Kefer Quaid in Idlib province . Activist groups , specifically the Syrian Observatory for Human rights , reported that 72 defectors were killed as they were gunned down during their attempted escape . The Syrian Army lost three soldiers during the clashes . The next day , S . O . H . R . stated that in all 100 defectors were killed or wounded . The clashes continued into the next day , and another report , by Lebanese human rights activist Wissam Tarif , put the death toll even higher with 163 defectors , 97 government troops and nine civilians killed on the second day alone as the military tracked down the soldiers and civilian that managed to initially escape . On 21 December , it was reported that the FSA had taken control over large swathes of Idlib province including some towns and villages . It was also reported on 24 December that the FSA stronghold in the Bab Amr neighbourhood of Homs was under attack by security forces , with two FSA soldiers killed . A week later , a minute long fire fight erupted between FSA forces and government security forces , on a road near the village of Dael in Daraa province . Four government soldiers were killed in the ambush . Armed action in 2012 . January . Clashes around Damascus . Syrian forces clashed with army deserters in an area near the capital Damascus , opposition activists said . The town of Reef Damascus saw fighting on 1 January as the government forces were hunting for suspected defectors , according to the activists . There were no immediate reports of casualties . According to the London based Syrian Observatory for Human rights , despite a self - declared ceasefire , Free Syrian Army soldiers in Idlib , on 2 January , overran two checkpoints belonging to security forces and captured dozens of loyalist troops , and launched an attack on a third checkpoint killing and wounding several loyalists . More than a dozen people , including 11 soldiers , were killed in clashes between defectors and loyalists in Basr al - Harir , a town in southern Daraa Governorate , according to the Syrian Observatory for Human Rights . Shelling and gunfire were also reported in Deir ez - Zor by the LCC . On 14 January , the Syrian Observatory For Human Rights said there was fighting between deserters and loyalist troops in Hula , Homs province , after the defectors destroyed a barricade and a number of security forces were killed or wounded . Battle of Zabadani . In mid - January , the FSA managed to take control over the border town of Zabadani , just 14 miles away from the capital , Damascus . Regular army forces tried to assault the town several times but as of 16 January all attacks were repelled . Battle for the Damascus suburbs . By 26 January , the Damascus suburb of Douma had fallen under control of the Free Syrian Army , with occasional raids by security forces failing to dislodge the rebels , mainly made of armed civilians , and some army defectors , mostly armed with assault rifles and hand grenades . Because of the growing number of defectors , some defectors managed to take their tanks with them . A spokesman for the Free Syrian Army said that more than 100 soldiers defected on 28 January 2012 , bringing three tanks along with them . By the end of January and the beginning of February , videos surfaced showing BMP - 2 armoured personnel carriers in Homs carrying the Syrian independence flag firing at government forces , supported by FSA soldiers . Between the 29 and 30 January , government forces massed over 2 , 000 troops and at least 50 tanks and launched a major offensive to reclaim the northern suburbs – held by the FSA – and drive them from the city . By the end of 30 January , it appeared that the operation had been mostly successful , and the FSA had made a tactical withdrawal . 10 FSA fighters and eight government soldiers were killed during the day in the whole country . Two of the defectors died in the Damascus suburb of Rankus , which had been retaken by the military . Another report put the day ' s death toll in the suburbs at 19 civilians and 6 FSA fighters , while the overall number of those killed in the previous three days , since the fighting in the area started , was 100 . The same day , it was reported by opposition activists that one of the original founders of the FSA , Colonel Hussein Harmush , who was captured in late August by Syrian special forces , was executed several weeks earlier . On 31 January , the Syrian army continued to advance in order to remove the last FSA pockets . The army fired into the air , as they advanced with tanks even beyond the positions from where the FSA withdrew . Activists told that the suburbs were on unannounced curfew while others were allowed to flee . The army was conducting arrests on suspected people in the district of Arbin . In some instances , curfews were defied by some citizens , who put up a large opposition flag in the centre of Damascus . February . Second battle of Rastan . The FSA during the Second Battle of Rastan retook complete control of the city of Rastan around early February . Damascus suburbs . On 1 February , the Syrian army extended their operations around Damascus , with more troops moving into the mountainous area of Qaramoun , north of Damascus . Further north , the troops which took the control of Rankous , started to extend their control into farmland surrounding the city . In the eastern suburbs of Mesraba , activist reported that army snipers were positioned and that tanks were in the streets . Initially , 12 people , including six FSA rebels , were killed in fighting in Wadi Barada , located north - west of Damascus in the Rif Damashk governorate , according to the Local Committee of Coordination . Later , the death toll of FSA fighters in the area was raised to 14 . The town of Deir Kanoun and Ein al Fija were also under army assaults according to the London based SOHR . At the same time , SANA reported that , further south in the suburbs Daraa , security forces killed 11 armed fighters and wounded two when they attacked a military bus killing one Army sergeant and wounding two others . Also , the Al - Watan newspaper reported that 37 rebel fighters were killed in fighting in Homs and 15 in Rastan , while four soldiers died in Bab Dreib and two in Rastan . According to the Syrian Observatory for Human Rights , troops and army defectors clashed in the northwestern province of Idlib and the southern province of Daraa on 5 February . They report two civilians and nine soldiers killed in Idlib . The FSA seems to have taken over another checkpoint in Homs on 2 February . Five government troops were shot in clashes with rebel fighters in Qalaat al - Madyaq town in restive Hama area , on 14 February . Homs bombardment . On the night of 3 February and in the early hours of 4 February , government forces launched a major offensive against Homs , leading to over 200 deaths and 800 injuries . FSA forces engaged loyalist forces and threatened reprisals particularly in Damascus . On 10 February , Sky News reported that the FSA had taken full control of the northern city of Idlib . However , Syrian tanks were surrounding Idlib , and citizens and defected soldiers feared a new offensive . Renewed fighting in the Idlib province was reported on 11 February . Battle of Al - Qusayr . Heavy fighting had taken place in the town of Al - Qusayr in Homs since 13 February , when the FSA captured the headquarters of the secret service in Homs , killing five agents in the process . Remaining government troops retreated to the town hall and hospital in the city . Four tanks came to reinforce them . However , 1 of the 4 tanks as well as 30 soldiers defected to the opposition , where the tank , aided by tractors and trucks , took out remaining government positions and the other 3 tanks . During the Battle of Al - Qusayr , FSA fighters were able to establish full control of the city . They said 20 government soldiers had been killed and 80 had fled . FSA fighters said 1 of their men had been killed and another 6 wounded during the battle . Battle of Baba Amr . Baba Amr district in Homs fell to government forces on the morning of 1 March , as the Free Syrian Army claimed they had made a " tactical retreat " from the area , after running low on weapons and ammunition . They made the decision to withdraw from Baba Amr and into other parts of Homs because " worsening humanitarian conditions , lack of food and medicine and water , electricity and communication cuts as well as shortages in weapons . " March . Second unsuccessful defection in Idlib . Shortly after their retreat from Baba Amr in Homs , the FSA suffered another setback on 3 March , when a defection of 50 soldiers from the Abu Athuhoor Military Airport in Idlib province was foiled after their plans were discovered . 47 of the soldiers were executed and only three managed to escape . Their bodies were reportedly dumped in a lake . Raid in Mezze . A raid was held in the Mezze area of Damascus , involving machine - gun fire and rocket propelled grenades . A defecting general was escorted from the area . A military helicopter flew over the area leading to the detection and deaths of 7 FSA fighters . Also , 80 elements of the security forces including pro - government militia were reportedly killed and 200 wounded during the clashes . The deputy commander of the Free Syrian Army also said that two military tanks were destroyed during the operation . However , neither the opposition - affiliated SOHR activist group or any independent media confirmed the high number of government casualties in the clashes . April . Homs situation . By late April 2012 , despite a cease - fire being declared in the whole country , heavy fighting continued in Al - Qusayr , where rebel forces controlled the northern part of the city , while the military held the southern part . FSA forces were holding onto Al - Qusayr , due to it being the last major transit point toward the Lebanese border . A rebel commander from the Farouq Brigades in the town reported that 2 , 000 Farouq fighters had been killed in Homs province since August 2011 . At this point , there were talks among the rebels in Al - Qusayr , where many of the retreating rebels from Homs city ' s Baba Amr district had gone , of Homs being abandoned completely . May . Despite the UN ceasefire , fighting between the Free Syrian Army and Syrian government forces continued throughout May . The FSA had used much of early May to regroup and gradually launched more and more attacks on government forces as the month progressed ( despite often being poorly armed ) and it became clear that the ceasefire had failed . Kofi Annan himself expressed exasperation at the ongoing violence . Footage in late - May appeared to show FSA forces had been destroying Assad forces ' tanks in Idlib . June . The Free Syrian Army announced on 4 June it was abandoning its ceasefire agreement . Spokesman Sami al - Kurdi told Reuters that the FSA had begun attacking soldiers to " defend our people " . At least 80 government soldiers were killed in escalating violence over that weekend . By mid - June , the FSA controlled large swathes of land in Idlib governorate and Northern Hama governorate . In these areas , the FSA and local individuals administered justice and the distribution of supplies to residents . It was reported on 28 June that the opposition almost entirely controlled the city of Deir ez - Zor , while the government army had shelled it , trying to take it back . Human rights groups said that this assault with tanks and artillery had killed over 100 residents . The government also reportedly told doctors not to treat people at local hospitals and targeted hospitals that refused with mortar rounds . Humanitarian aid workers from the Syrian Arab Red Crescent were targeted by the army , one worker was killed . In Homs , the FSA held out against government forces bombarding large parts of the city , including the opposition bastion of Khaldiyah . Also , renewed fighting between rebels and loyalists was reported in the Baba Amr neighourhood of Homs . July . In July , it was reported that the Free Syrian Army had taken control of a number of suburbs north of the capital Damascus , including Zamalka and Irbeen . FSA fighters openly patrolled the streets of the suburbs , and clashes occurred less than 10 kilometers from the center of Damascus city itself . It was reported that the Free Syrian Army also took control of a commercial crossing in Bab al - Hawa in Syria ' s northern frontier . FSA fighters had fought government forces there for ten days until they won . FSA fighters were seen in video footage , destroying portraits of Assad and celebrating their victory . November . On 18 November , rebels took control of one of the Syrian Army ' s largest military bases in northern Syria , Base 46 in the Aleppo Governorate after weeks of intense fighting with government forces . Defected General Mohammed Ahmed al - Faj , who commanded the assault , hailed the capture of Base 46 as “ one of our biggest victories since the start of the revolution ” against Bashar al - Assad , claiming nearly 300 Syrian troops had been killed and 60 had been captured with rebels seizing large amounts of heavy weapons and tanks . On 22 November , rebels captured the Mayadeen military base in the country ' s eastern Deir ez Zor province . Activists said this gave the rebels control of a large amount of territory east of the base , to the Iraqi border .