Operation Chenla II or Chenla Two was a major military operation conducted by the Khmer National Armed Forces (FANK) during the Cambodian Civil War from 20 August until 3 December 1971. Background During the days of Prince Norodom Sihanouk's rule in Cambodia in the 1960s, the People's Army of Vietnam (PAVN) and their Viet Cong (VC) allies were able to use base areas in Cambodian territory in order to provide logistical support for their combat troops within South Vietnam. Following the March 1970 coup led by the pro-U.S. General Lon Nol, the PAVN aggressively expanded their control over the provinces of northeastern Cambodia, coming dangerously close to the capital Phnom Penh. Initially, the small, largely untrained and poorly-equipped FANK was not up to the challenge, especially against the larger and more experienced PAVN/VC forces. However, by the summer of 1971, and with massive American and South Vietnamese assistance, the FANK grew into a force of more than one-hundred thousand men. During the period between September 1970 and June 1971, the FANK won its first victories after they successfully dislodged elements of the PAVN 9th Division along Route 13 and in some parts of the Mekong Delta. By April 1971, Marshal Lon Nol decided to renew the offensive against the PAVN/VC forces, taking advantage of the high morale among the FANK troops following the partial success of Operation Chenla I. For the FANK everything was at stake, as many reserves and prestige were invested in the operation. The FANK High Command's main objective was to reopen all of Route 6 and to secure the road between Kampong Cham and the isolated garrison at Kampong Thom. A FANK task-force of ten infantry battalions – again including a large percentage of Khmer Krom troops – gathered into three brigade groups supported by armour and artillery was assembled for the operation, which relied heavily on U.S. air support to soften an estimated two PAVN divisions in the region. Operation Operation Chenla II was launched on 20 August 1971, again catching the PAVN/VC by surprise. Initially, the FANK task-force commanded by Brigadier-General Hou Hang Sin achieved their objective, as the FANK were able to retake Barai on 26 August and Kompong Thmar on 1 September. But as FANK formations were advancing towards PAVN/VC-held territory along Route 6, they were heavily exposed to attacks without adequate protection from their flanks. There was heavy fighting as the