Cambodia's new government said yesterday that its forces captured ousted premier Pol Pot's headquarters when they overran the border town of Pailin on Tuesday and Pol Pot and his "clique" filed across the border into Thailand with many of their troops.

Thai military sources in Bangkok were unable to confirm the report that Pol Pot had escaped to Thailand. On Tuesday, however, they had reported the capture of Pailin by the new Vietnamese-backed government in Phnom Penh. Pailin was the last town known to be controlled by the Pol Pot forces.

The Thai sources said that heavy fighting was going on in the border region and that Pol Pot's forces may have captured parts of the strategic border town of Poipet. More than 170 Cambodian soldiers of the Vietnamese-backed government that guarded Poipet crossed into Thailand early this morning and surrendered to the Thai border guard, they said.

In making the claim that it has captured Pol Pot's headquarters, the Cambodian government also said that it had seized a large enemy base camp and about 1,000 soldiers. More than 100 vehicles were destroyed in the camp, and large amounts of weapons, some artillery and food supplies were seized, the report said.

Meanwhile, a group of 216 Vietnamese refugees from the frighter Tung An left for Canada aboard a chartered plane. It was the single biggest resettlement of passengers on the freighter which has been in Manila Bay for three months.

The Canadian Embassy in Manila said the 216 were the first of 500 it planned to send from the Philippines this month. CAPTION: MAP, no caption, By Dave Cook-The Washington Post