<P> In Operation Gibraltar, 224 soldiers of the First Brigade of the 101st Airborne landed by helicopter near An Khê, in the Central Highlands area where 2 Viet Cong battalions were located . The Viet Cong attacked and killed 13 Americans . Air strikes forced the Viet Cong to retreat, with losses estimated by the U.S. at between 226 and 257 . General Westmoreland called the operation "a great victory ." Others, including Col. David H. Hackworth, considered the battle "not...a great victory ." </P> <Dl> <Dt> 20 September </Dt> </Dl> <P> Seven U.S. warplanes were shot down over North and South Vietnam . </P> <Dl> <Dt> 22 September </Dt> </Dl>

Intensification of american military buildup in vietnam happened under