 Within two months , however , the limit of the operational area was extended past the Mekong , and U.S. tactical aircraft were soon directly supporting Cambodian forces in the field . These missions were officially denied by the U.S. and false coordinates were given in official reports to hide their existence . Defense Department records indicated that out of more than 8 @,@ 000 combat sorties flown in Cambodia between July 1970 and February 1971 , approximately 40 percent were flown outside the authorized Freedom Deal boundary . 
