Secretary of State Hillary Rodham Clinton on Thursday wrapped up three days of intense Middle East diplomacy that produced good atmospherics but no sign that an impasse over Israeli settlement construction has been resolved.

"We all know that there is no alternative to peace other than negotiating peace, so we have no alternative but to continue peace efforts," Palestinian Authority President Mahmoud Abbas said before meeting with the chief U.S. diplomat in the West Bank city of Ramallah.

But Abbas gave little indication that he was willing to keep talks going after a partial moratorium on Israeli settlement construction expires Sept. 30.

Egyptian President Hosni Mubarak told Israel Television that he asked Israeli Prime Minister Binyamin Netanyahu to extend the 10-month moratorium by three months, during which the borders of a Palestinian state could be negotiated. Building could subsequently resume within Israel's presumed future borders, but not beyond them.

On Wednesday evening, Netanyahu told Abbas during talks at his residence in Jerusalem that the moratorium would not be extended, Israeli media reported. The prime minister's office repeated that position in a statement Thursday.

But Netanyahu has indicated that some restrictions on construction will be applied, and U.S. officials are hoping that the momentum of the past few days will persuade the Palestinians to keep talking, even if the settlement freeze is not extended in full.

In an interview with Israel's Channel 10 television, Clinton said the administration has pushed for flexibility on the moratorium, such as a limited extension.

"It takes time, all of this is complicated," Clinton said. "But where we sit now, it would be useful for some extension, it would be extremely useful. And I don't think a limited extension would undermine the process going forward."

U.S. officials also recognize, however, that the Israeli leader is under intense pressure from members of his right-wing coalition to lift the freeze.

Abbas and Netanyahu, accompanied by Clinton and U.S. special envoy George Mitchell, spent more than four hours in direct talks this week, first in Egypt on Tuesday and then in Israel on Wednesday. Aides to the two men are scheduled to continue negotiations next week, but no date has been set for another meeting at the leadership level.

Clinton said in the interview that both leaders had grappled early with core issues in dispute.

"They're not wasting any time. They're getting right into talking about the most sensitive, most difficult issues," Clinton said.

She added: "From what I've seen, it could go on a very fast track to either an agreement or to agreement on certain things, and I hope that it continues."

On Wednesday, Mitchell made similar remarks, though few details of the talks have leaked. "They are serious, they mean business," he said of Netanyahu and Abbas.

"I will say that the two leaders are not leaving the tough issues to the end of their discussions," Mitchell added. "We take this as a strong indicator of their belief that peace is possible."

But Mitchell refused to say whether the United States was confident the Palestinians would keep talking after the end of the month. "That subject was discussed this evening. We continue in our efforts to make progress in that regard and believe that we are doing so," he said.