Vietnam ground combat operations in 1965, and at their peak they numbered more than 500,000. The US also engaged in a sustained aerial bombing campaign. Meanwhile, China and the Soviet Union provided North Vietnam with significant material aid and 15,000 combat advisers. Communist forces supplying the Việt Cộng carried supplies along the Hồ Chí Minh trail, which passed through the Kingdom of Laos. The communists attacked South Vietnamese targets during the 1968 Tết Offensive. Although the campaign failed militarily, it shocked the American establishment, and turned US public opinion against the war. During the offensive, communist troops massacred over 3,000 civilians
Vietnam War saw extensive action during the Vietnam War, and over 600 were deployed with US Forces. Ground forces also had access to B-52 and F-4 Phantom II and others to launch napalm, white phosphorus, tear gas and chemical weapons, precision-guided munition and cluster bombs. The Vietnam War was the first conflict where U.S. forces had secure voice communication equipment available at the tactical level. The National Security Agency ran a crash program to provide U.S. forces with a family of security equipment, code named NESTOR, fielding 17,000 units initially; eventually 30,000 units were produced. However, limitations of the units, including poor