a broad, non-communist front against the invaders, with a prominent role given to Sihanouk. China sent its vice premier, Geng Biao, to Thailand to negotiate the shipment of arms to the Khmer Rouge through Thailand. China also sent diplomats to stay with the Khmer Rouge encampments near the Thai border. Pol Pot met with these diplomats twice before the Chinese government withdrew them for their safety in March. In China, the Khmer Rouge set up their "Voice of Democratic Kampuchea" radio station, which remained their main outlet for communicating with the world. In February, the Chinese attacked northern Vietnam, hoping to draw Vietnamese troops away from the invasion of Cambodia. As well as China, the Khmer Rouge also received the support of the United States and most other non-Marxist southeast Asian countries who feared Vietnamese aggression as a tool of Soviet influence in the region. On 15 January, the Vietnamese reached Sisophon. Pol Pot, Nuon Chea, and Khieu Samphan then moved to Palin on the Thai side of the border, and in late January relocated again, to Tasanh, where Sary joined them. There, on 1 February, they held a Central Committee conference, deciding against Deng's advice about a united front. In the second half of March, the Vietnamese moved to hem in the Khmer Rouge along the Thai border, where many of Pol Pot's troops had crossed into Thailand itself. The Vietnamese advanced on Tasanh, from which the Khmer Rouge leaders had fled only a few hours before it was captured. After Democratic Kampuchea Fighting back against the Vietnamese: 1979–1989 In July 1979, Pol Pot established a new headquarters, Office 131, on the western flank of Mount Thom. He dropped the name "Pol Pot" and began calling himself "Phem". In September 1979, Khieu announced that the Khmer Rouge was establishing a new united front, the Patriotic Democratic Front, bringing together all Cambodians who opposed the Vietnamese occupation. Senior Khmer Rouge members began disavowing the cause of socialism. The group members stopped wearing uniform black outfits; Pol Pot himself started wearing jungle green fatigues and later Thai-made safari suits. Short believed that these changes reflected a genuine ideological shift in the Khmer Rouge. In October, Pol Pot ordered an end to executions, a command which was largely followed. In November 1979, the United Nations General Assembly voted to recognise the Khmer Rouge delegation, rather than that of the Vietnamese-backed government, as