Soviet and Afghan officials and Afghan rebels staked out their positions yesterday in advance of crucial U.N.-mediated peace talks scheduled to resume in Geneva on March 2.

Soviet First Deputy Foreign Minister Yuli Vorontsov ended two days of talks with Pakistani officials in Islamabad without reaching agreement on forming an interim government for Aghanistan. Pakistani President Mohammed Zia ul-Haq, in an interview appearing in The Washington Post last month, declared that Pakistan could not sign any agreement with the present, Soviet-backed government in Kabul.

"Nobody will try to form a government for Afghanistan from outside," Vorontsov told reporters at Islamabad's airport. "It is nobody's business but the business of the Afghans themselves."

The chairman of Afghanistan's High Commission for National Reconciliation, Abdul Rahim Hatif, stressed the same point in a news conference in Geneva. "We do not accept the dictates of anybody in regard to the form of govenrment within Afghanistan -- neutral, nonaligned or any type of coalition or one-party government," Hatif said. "That is a problem which totally depends upon the Afghans themselves, not on Zia ul-Haq or anybody else."

On Monday, Soviet leader Mikhail Gorbachev and Afghan President Najibullah announced that Soviet troops could begin leaving Afghanistan on May 15 and complete their pullout in 10 months if an agreement is signed in Geneva by March 15. Both Gorbachev and Najibullah rejected Zia's effort to tie a withdrawal pact to formation of a new coalition government that would include the anticommunist rebels based in Pakistan.

Leaders of the seven U.S.-backed rebel groups met for eight hours on Wednesday to draft a joint position on an interim government for Afghanistan. A spokesman said they had agreed on a government that would exclude communist participation, United Press International reported from Islamabad, but he refused to give any details on who would be included.

The seven rebel parties are divided along religious and ideological lines. The leader of one of the most fundamentalist groups, Gulbuddin Hakmatyar, said Wednesday night that the seven groups had decided to share Cabinet posts, but he provided no details.

In Geneva, Hatif, who said he is not a member of Najibullah's People's Democratic Party of Afghanistan, declared, "There is no question that Dr. Najibullah or the People's Democratic Party will be excluded from power."

Vorontsov, as he left Pakistan, treated the issue as an obstacle to a Soviet withdrawal. "Any delays in the signing of the Geneva accords will mean only one thing, and that will be a delay in the withdrawal of Soviet forces," he said. "We don't know who will take that responsibility."

Asked whether Moscow could withdraw its troops, estimated at 115,000 to 120,000, without an agreement in Geneva, Vorontsov left that possibility open, replying, "It's not in the plans now."