President Bush expressed optimism on Wednesday that the Israelis and Palestinians could negotiate a peace agreement as Secretary of State Condoleezza Rice ended four days of talks here with a spasm of discord between the sides.

Secretary of State Condoleezza Rice, right, ducked to enter the Church of the Nativity in Bethlehem during a visit Wednesday.

After what appeared to be a tense meeting with Ms. Rice, the Palestinian president, Mahmoud Abbas, accused Israel of failing to take the peace process seriously by refusing to discuss issues he considered essential to holding the international conference Mr. Bush has proposed for this fall.

“It’s impossible to go to the conference at any price,” Mr. Abbas said after meeting with Ms. Rice at the presidential compound in Ramallah.

Israel’s foreign minister, Tzipi Livni, responded by saying it served no purpose to negotiate delicate questions about the future of a Palestinian state in public. She declined, when asked, to discuss Palestinian demands that any conference include talks on borders, a future capital in Jerusalem, refugees and Israeli settlements in Palestinian territories.

“The idea is not to raise expectations that can lead to frustration and to violence,” she said, voicing widely held Israeli skepticism.

Ms. Rice, making her seventh trip to the region this year and the most extensive one yet, has tried to get the sides to agree on a written statement that would outline the scope of the international conference, planned for Annapolis, Md., possibly in November.

The meeting’s timing appeared increasingly uncertain on Wednesday, with continuing clashes in the Palestinian territories and steps by Israel that Mr. Abbas’s spokesman, Nabil Abu Rudeineh, said were “hindering the endeavor to reach a substantive document to go to the conference.”

In Washington, Mr. Bush did not respond directly to Mr. Abbas’s warnings, but he said he remained confident that progress could be made.

“The attitude is, let’s work together to see if we can’t lay out that vision for the sake of peace between Israel and the Palestinians,” he said at a news conference. “And it’s possible.”

Ms. Rice spent an unusually large part of her time here meeting not only with political leaders, like Prime Minister Ehud Olmert, at a working dinner on Wednesday night, but also with religious figures, business executives and other civic leaders.

Her aides described the encounters as an effort to break out of the confines of diplomatic meetings. “You understand, given the nature of the jobs,” a senior official said, “everywhere you go you’re in a bubble.”

On Wednesday, the secretary traveled to Bethlehem, a city hemmed inside the West Bank by the barrier the Israelis have built. Ms. Rice, a daughter and granddaughter of Presbyterian ministers, visited the Church of the Nativity, built on the biblical birthplace of Jesus Christ, where she spoke of her own faith. “I think I could spell Bethlehem before I could spell my name,” she said.

She added that a largely Muslim city like Bethlehem, which also includes Rachel’s Tomb, a sacred site for Jews, was a model for reconciliation. As she visited, Israeli jets roared overhead.

Samir Hazboun, director of a research and consulting organization and a member of the Bethlehem Chamber of Commerce, said that he and others there had told Ms. Rice that actions Israel considered necessary for its security were harming the Palestinian economy and the ability of the Palestinian Authority to provide basic government functions and security.

“We have high expectations from the Americans,” he said. “We see this as the last opportunity.”