On 2 July 1976, North and South Vietnam were merged to form the Socialist Republic of Việt Nam. The war left Vietnam devastated, with the total death toll between 966,000 and 3.8 million. A 1974 US Senate subcommittee estimated nearly 1.4 million Vietnamese civilians were killed or wounded between 1965 and 1974—including 415,000 killed. In its aftermath, under Lê Duẩn's administration, there were no mass executions of South Vietnamese who had collaborated with the US or the defunct South Vietnamese government, confounding Western fears, but up to 300,000 South Vietnamese were sent to reeducation camps, where many endured torture, starvation, and disease while being forced to perform hard labour. The government embarked on a mass campaign of collectivisation of farms and factories. In 1978, in response to the Khmer Rouge government of Cambodia ordering massacres of Vietnamese residents in the border villages in the districts of An Giang and Kiên Giang, the Vietnamese military invaded Cambodia and removed them from power after occupying Phnom Penh. The intervention was a success, resulting in the establishment of a new, pro-Vietnam socialist government, the People's Republic of Kampuchea, which ruled until 1989. This, however, worsened relations with China, which had supported the Khmer Rouge. China later launched a brief incursion into northern Vietnam in 1979, causing Vietnam to rely even more heavily on Soviet economic and military aid, while mistrust of the Chinese government began to escalate.