month after the fall of Phnom Penh against several unsuccessful attempts by Khmer Rouge forces to reduce this last holdout. The Khmer Rouge finally succeeded on May 22, after shelling the hill where the temple stands, scaling it, and routing the defenders, as Thai officials reported at the time. Command structure Regional Commands Prior to the War, Cambodia was divided into seven military districts termed 'Military Regions' (MR, ) encompassing one to ten military sub-districts () of unequal size roughly corresponding to the areas of the country's 23 provinces and districts. They were organized since September 1969 as follows: First Military Region () – headquartered at Kampong Cham, capital of Kampong Cham Province, the MR 1 covered the Kampong Cham, Prey Veng, and Svay Rieng military sub-districts. Second Military Region () – headquartered at Kampong Speu, capital of Kompong Speu Province, the MR 2 covered the Kampong Speu, Kampot, Takéo, Srakar Neak, Kampong Seila, Thmar Keo, Kirirom, Kep-Bokor, and Koh Kong military sub-districts. Third Military Region () – headquartered at Battambang, capital of Battambang Province, the MR 3 covered the Battambang, Pursat, Thmar Pouk, Stung Meanchey, and Kampong Chhnang military sub-districts. Fourth Military Region () – headquartered at Siem Reap, capital of Siem Reap Province, the MR 4 covered the Siem Reap, Kampong Thom, Preah Vihear, Oddar Meanchey, and Angkor Chum military sub-districts. Fifth Military Region () – headquartered at Stung Treng, capital of Stung Treng Province, the MR 5 covered the Stung Treng and Ratanakiri military sub-districts. Sixth Military Region () – headquartered at Kratié, capital of Kratié Province, the MR 6 covered the Kratie and Mondulkiri military sub-districts. Phnom Penh Special Military Zone (PPSMZ, ) – headquartered at Phnom Penh, it covered the National Capital zone and its environs, the Udong Meanchey and Kandal military sub-districts. The 6th MR and its regional HQ at Kratie were lost permanently upon the desertion of the local Cambodian garrison troops to the enemy soon after the beginning of hostilities. A special military zone for the lower Mekong River, designated the Special Mekong Zone – SMZ or 12th Tactical Zone (French: Zone Spéciale du Mekong – ZSM; Zone Tactique 12) was established in mid-1971 at Kandal Province, situated between the Cambodian Capital and the South Vietnamese border. Two additional military regions (8th MR and 9th MR) were created in 1973. Branches The FANK's predecessor was first established on November 9, 1953 under