Moscow to help speed Vietnam pullout. TURNING POINT FOR CAMBODIA?

The Soviet Union has hinted it will help end Vietnam's occupation of Cambodia and hopes Hanoi will withdraw all its forces next year. Moscow is prepared to ``assist in the progress of the external aspect of the [Cambodian] problem,'' Soviet Vice Foreign Minister Igor Rogachev said in remarks on last week's Sino-Soviet talks on the conflict.

Before leaving Peking last Friday, the Soviet envoy said a Vietnamese pullout would promote a normalization of Sino-Soviet political ties.

China has demanded that Moscow urge Vietnam to remove its estimated 100,000 to 120,000 troops from Cambodia as the sole major condition for a rapproachment of relations strained since 1960.

For their part, ``The Soviets in principle agree that Vietnam should withdraw as soon as possible,'' said Vice Foreign Minister Tian Zengpei, Peking's chief negotiator.

Both the Chinese diplomat and his Soviet counterpart said they found grounds for wider agreement during a five-day ``working meeting'' on Cambodia. But, said Mr. Rogachev, ``this does not mean that we have no points of difference.''

China and the Soviet Union have not set a timetable for a Vietnamese withdrawal, said Soviet Embassy spokesman Vladimir Veselov. The Chinese want a withdrawal ``after the end of this year,'' he said, indicating that Moscow needs more time.

On the complex question of Cambodia's future government, Rogachev said that Peking and Moscow share a ``very clear'' understanding that ``as far as internal aspects of the problem are concerned, this is a matter for Kampucheans [Cambodians] themselves to decide.''

However, negotiators appeared to make less headway on the knotty question of who should rule while Vietnam withdraws and until general elections can be held.

Peking supports the creation of a provisional four-party coalition government headed by exiled Cambodian ruler Prince Norodom Sihanouk and composed of all three Cambodian resistance factions and the Hanoi-installed Phnom Penh regime. China is the main arms supplier to the Cambodian resistance, and it vowed last month to continue its support until Vietnam withdraws.

This would mean dissolving the current Phnom Penh regime and granting a role in the coalition to the Peking-backed Khmer Rouge guerrillas, the strongest rebel force with an estimated 30,000 troops.

Moscow's ally, Vietnam, has resisted dismantling the current regime, which Hanoi put in place following its invasion of Cambodia in late 1978.

Moreover, Vietnam has demanded the elimination of the communist Khmer Rouge army and its leaders, whose rule left an estimated 1 million people dead.

In a compromise gesture supported by Peking, the Khmer Rouge agreed three weeks ago to disband its ``Democratic Kampuchea'' party if the Hanoi-backed ``People's Republic of Kampuchea [PRK]'' were dissolved at the same time.

Moscow has rejected the proposal, the Soviet spokesman indicated Friday. Instead, it called for a ``reconciliation'' of the four Cambodian factions, according to Mr. Tian.

It was unclear Friday whether Soviet support for a ``reconciliation'' signaled a move toward acceptance of Peking's proposed four-party coalition government, or merely echoed Phnom Penh's July offer to create a ``national reconciliation council'' of the four groups while continuing to rule Cambodia.

Tian indicated that Peking and Moscow also failed to agree on what role international supervision and peace-keeping groups would play.

On Aug. 26, Chinese Communist Party chief Zhao Ziyang pledged Peking's support for a peace-keeping force and an ``international supervision committee'' to guarantee the establishment of a quadripartite coalition led by Prince Sihanouk.

According to Tian, Moscow stopped short of joining China in approving an international peace-keeping force. ``The Soviet Union in principle agreed to have international supervision, but I'm not clear on the details,'' Tian told reporters.

Soviet Foreign Minister Eduard Shevardnadze and his Chinese counterpart Qian Qichen are expected to discuss Cambodia this month at the UN in New York, Rogachev said.