A spokesman for the Palestinian president, Mahmoud Abbas, who has staked his own reputation on the peace effort, described Mr. Olmert’s resignation plans on Wednesday as an “internal affair.” The spokesman, Nabil Abu Rudeineh, said, “The Palestinian Authority deals with the prime minister of Israel, regardless if he is Olmert or somebody else.”

Mr. Olmert said that Israel was “closer than ever” to reaching understandings that might serve as a basis for agreements with the Syrians and the Palestinians, adding that he would work until his last day in office to bring the negotiations to a successful conclusion “that bears hope.”

So far, however, six months of talks with the Palestinians have not yielded any obvious results, while Syria continues to insist on talking to Israel indirectly through Turkish mediators.

Mr. Olmert’s drive for diplomatic achievements “might frighten some,” said Abraham Diskin, a political scientist at the Hebrew University of Jerusalem. There are Israelis who do not believe in agreements, and others who support the peace effort but do not feel comfortable having their leader negotiate desperately with an eye on the clock. “I belong to that second category,” Mr. Diskin said.

The future of the talks will depend largely on who emerges as Israel’s next leader.

The leadership race in the governing Kadima Party has been set for Sept. 17, with a runoff, if necessary, on Sept. 24. The main contenders are Foreign Minister Tzipi Livni, who leads the Israeli team in talks with the Palestinians, and Shaul Mofaz, the more hawkish transportation minister who is a former defense minister and a former army chief of staff.

In recent polls, Ms. Livni was leading, but Mr. Mofaz was closing the gap.

Mr. Olmert had left open the possibility of competing himself until Wednesday, though few expected that he would.

Although Mr. Olmert has pledged to resign after the vote, he will remain as a transitional prime minister until his successor can form a new government able to garner a majority of 61 votes in the 120-seat Parliament. That government would try to survive until a general election scheduled for 2010.