Foreign Minister Moshe Dayan warned tonight that there may be no more resumption of peace talks between Israel and Egypt if President Anwar Sadat insists on an Israeli commitment in advance to dismantle its settlements in the Sinai.

"If Sadat wants such assurances before the political committee can resume its deliberations, this looks to me like an impasse," Dayan said. "There very well may be no further talks."

The Israeli foreign minister sounded gloomy and unusually pessimistic tonight as he assessed the events of the past few days in a live interview on Israeli television.

Dayan said he felt the U.S. role would become even more crucial in the efforts that will have to be made now to maintain at least some of the peace momentum built up in the past two months.

"Without the United States, I do not see how we can make progress with Egypt," he declared.

Nevertheless Dayan did keep alive the possibility that Israel might decide to send Defense Minister Ezer Weizman back to Cairo next week to resume discussions with Egypt at the military level.

"We shall discuss the matter in the Israeli Cabinet on Sunday," Dayan said. "Much will depend on what Sadat will say in his speech to the Egyptian National Assembly tomorrow."

"Even more important will be the message that Assistant Secretary of State Alfred L. Atherton will bring with him when he returns from Secretary of State Cyrus) Vance's Cairo talks," Dayan said. Atherton is expected to arrive in Israel Sunday.

Dayan, in the interview, emphasized that while Israel was determined not to give advance commitments to Egypt on withdrawal, it was perfectly willing to discuss the subject in the Jerusalem political negotiations.

"We are ready to discuss the evacuation of our settlement points and all territories -- and the Egyptians know it," he said. "But we are not prepared to commit ourselves before discussions."

According to Dayan, in the many contacts that Israel has had with Sadat in the last two months, the question of the Israeli settlements in northern Sinai was never presented as a precondition for negotiations.

"We assumed that he knew that a certain reality had been created as a result of the wars between us, that there are settlements and that there are airfields, Dayan said. "We always made it clear that we consider this reality a subject for negotiation.

"If the Egyptian president felt that without our prior agreement to remove them, there could be no talks, he should have said so before the summit meeting at Ismailia and before the political committee's sessions in Jerusalem," he added.

Dayan also noted that Egyptian demands for Israeli withdrawal from occupied Arab territory included areas which were captured by force in 1948, such as the Jewish quarter of the Old City of Jerusalem.

The Egyptian president also demanded Israeli's withdrawal from the Golan Heights as part of his argument that territory cannot provide security, and that peace is a better guarantee of security, Dayan said.

"How can he talk for President Assad?" the foreign minister asked.

Dayan said that in a long talk with Egyptian Foreign Minister Mohammed Kamel before the Egyptian delegation departed Wednesday night, he got the impression that attacks in the Arab media on Egypt's so-called concilatory position may have been a factor in Sadat's decision to break off the talks.

Praising the role played by the United States in the negotiations to date Dayan said an even more active American role will be required in the weeks ahead. He did not exclude the possibility that Washington may apply pressure for concessions on Israel if the U.S. involvement increases.

"Perhaps we will be faced with American demands that we shall have to reject," Dayan said. "But this is a chance we must take."