page_title: 1966 in the Vietnam War
section_title: December
hierarchical_section_title: 1966 in the Vietnam War / December
context_page_description: At the beginning of 1966, the number of U.S. military personnel in South Vietnam totaled 184,314. South Vietnamese military forces totaled 514,000 including the army and the Regional Force and Popular Force militias. The North Vietnamese People's Army of Vietnam numbered 400,000, most still in North Vietnam. 50,000 PAVN cadre and soldiers infiltrated South Vietnam during 1965. Group 559, charged with transporting supplies down the Ho Chi Minh Trail to supply PAVN troops in both South Vietnam and Laos, numbered 24,400 personnel. The U.S. estimated the number of Viet Cong and PAVN soldiers in South Vietnam at nearly 280,000 by June 1966, including part-time guerrillas. A pause in the bombing of North Vietnam by U.S. warplanes had been announced by President Johnson on 24 December and remained in effect.
context_section_description: December - 15 December 1967
  Operation Fairfax was a joint counterinsurgency/pacification operation conducted by II Field Force, Vietnam and the ARVN in Gia Định Province near Saigon. The operation resulted in 1,200 VC killed or captured.
  4 - 5 December
  The VC conduct a sapper and mortar attack on Tan Son Nhut Air Base. The attack resulted in 28 VC killed and four captured, three U.S. and three ARVN killed. Twenty aircraft were damaged and three vehicles destroyed.
  7 December
  Trần Văn Văn, considered a leading candidate for President of South Vietnam, was assassinated by the VC in Saigon after leaving the office of Prime Minister Kỳ. Tran, a 58 year old politician who had formerly been the Secretary General of the nation's High National Council, had recently been elected as to the 117 member assembly that was to draw up a new constitution. He was riding in a car when a VC on a motorcycle pulled alongside and killed him with four shots.
  10 December
  Sixteen U.S. Marines were killed and 11 others injured when a Marine bomber accidentally dropped two 250 pound bombs on them. The Marines were fighting near Đông Hà in Quảng Trị Province, when they came under a mortar attack, and were firing their own 81 mm shells when the bombs "either bounced off a ridge of boulders, or fell about 300 yards (270 m) yards from their intended target."
  13 December
  The U.S. Department of Defense confirmed for the first time that a USAF pilot was being held captive in the People's Republic of China, after his F-104 Starfighter went down over China's Hainan Island. China had long maintained that it had an American pilot who had been captured alive in its territory. The United States said that Captain Philip E. Smith had either been shot down or had had a mechanical failure on 20 September 1965.
  19 December
  MACV's long-standing estimates were that the PAVN/VC forces in South Vietnam numbered 282,000. CIA analyst Sam Adams wrote a memo stating that "the number of Viet Cong is closer to 600,000 and perhaps more." The memo would initiate a lengthy debate between MACV and the CIA concerning the number of VC. 
  The U.S. Army deployed its new Mobile Riverine Force into combat for the first time, with the 2nd Brigade of the 9th Infantry Division arriving at Vung Tau.
  23 December
  The destroyer USS O'Brien became the first U.S. ship to be struck by shells fired from North Vietnamese shore batteries in Quảng Bình Province killing two crewmen and wounding four.
  24 December
  A Flying Tiger Line Canadair CL-44 cargo plane crashed into the Hòa Vang District of Da Nang, killing at least 125 civilians and the plane's crew of four. The four-engine turboprop fell short of the runway as it attempted to land in fog at Da Nang Air Base.
  Starting at 07:00 a 48-hour holiday ceasefire went into effect, five hours into the ceasefire, however, Australian troops were fired upon by VC near Saigon and six other incidents took place, including a small arms and mortar fire attack near Phú Lộc in Thừa Thiên Province, that killed an ARVN soldier.
  25 December
  The New York Times published a front page investigative report, "A Visitor to Hanoi Inspects Damage Laid to U.S. Raids", filed by editor Harrison E. Salisbury stating "Contrary to the impression given by U.S. communiques on-the-spot inspection indicates that U.S. bombing has been inflicting considerable civilian casualties and its environs for some time past."
  27 December
  The PAVN 22nd Regiment attacked Firebase Bird located in the Kim Son Valley and occupied by C Battery 6th Battalion, 16th Artillery and B Battery 2nd Battalion, 19th Artillery and defended by elements of the 1st Battalion, 12th Cavalry. The PAVN breached the perimeter and occupied most of the artillery positions, but were eventually forced out. The U.S. lost 27 killed in the attack and 267 PAVN were killed in the attack and the four day pursuit of the attacking unit.
  30 December
  U.S. and ARVN troops crossed the border into the Svay Rieng Province of Cambodia in pursuit of a fleeing VC force, and conducted a ground and air assault on the village of Ba Thu.
  Operati
caption: A Mobile Riverine Force boat fires a flamethrower
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