In late 1971, the People's Army of Vietnam launched Campaign Z into northern Laos, escalating the war in Laos with the aim of defeating the last Royal Lao Army troops. The NVA troops numbered 27,000 and brought with them 130mm field guns and T-34 tanks, while the North Vietnamese air force launched MiG-21s into Lao air space. General Giap's specific orders to this task force were to kill the CIA army under command of the Hmong war lord Vang Pao and occupy its field headquarters in the Long Tieng valley of northeast Laos.brbrThey faced the rag-tag army of Vang Pao, fewer than 6,000 strong and mostly Thai irregulars, recruited by the Thai army to fight for the CIA in Laos. By the time the NVA launched their first attack, 4,000 Tahan Sua Pran had been recruited, armed, trained and rushed in position in Laos to defend against the impending NVA invasion. They reinforced Vang Pao's indigenous army of 1,800 Lao hillstribe guerrillas.brbrDespite the odds being overwhelmingly in the NVA's favor