In 1953, Pathet Lao fighters accompanied an invasion of Laos from Vietnam led by Viet Minh forces; they established a government at Viengxay in Houaphan province in northeast Laos. The communists began to make incursions into central Laos with the support of the Viet Minh, and a civil war erupted; the Pathet Lao quickly occupied substantial sections of the country.
The 1954 Geneva Conference agreements required the withdrawal of foreign forces, and allowed the Pathet Lao to establish itself as a regime in Laos' two northern provinces.