The White House acknowledged for the first time on Thursday that Israel and the Palestinians were unlikely to reach a peace deal before President George W. Bush leaves office in January.

U.S. Secretary of State Condoleezza Rice, beginning a four-day visit to the Middle East, said Israel's decision to call a parliamentary election, scheduled for February 10, had created a "different situation" that made it "very difficult" to come to an agreement.

In Washington, White House spokeswoman Dana Perino also cast strong doubt on the prospects of an agreement, saying: "No, we do not think that it's likely that it would happen before the end of the year."

Bush had hoped an end-of-term deal would bolster a legacy burdened by the war in Iraq. But the peace talks, launched nearly a year ago at a conference in Annapolis, Maryland, have been hobbled from the start by violence and bitter disputes over Jewish settlement building and the future of Jerusalem.

U.S. officials said Rice, whose trip includes stops in the Palestinian territories, Jordan and Egypt, had no plan to float her own proposals to strive for a last-minute deal.

"Obviously, Israel is in the midst of elections and that is a constraint on the ability of any government to conclude what is the core conflict ... for Israel and the Palestinians and has been for 40 years," Rice told reporters as she flew to Tel Aviv, where she met outgoing Israeli Prime Minister Ehud Olmert and Foreign Minister Tzipi Livni.

While Israeli-Palestinian peace talks are expected to continue next year, Israel's political uncertainty and Barack Obama's victory in the U.S. presidential election on Tuesday leave the Bush administration with limited influence in its waning days. Obama takes office on January 20.

Rice made clear her goal was to lay the ground for continued talks but she said it was an "open question" how the Bush administration would hand over the process.

She said Israeli and Palestinian leaders would "affirm that the Annapolis process, and the framework that it establishes, is indeed the basis on which they believe they can come to a resolution of their conflict, ... regardless of anyone's timetable."

ANOTHER VACUUM?

Palestinian negotiator Saeb Erekat expressed concern that Israel would fill the "vacuum" in the run-up to the February election "with more settlements and Israeli military campaigns."

Livni, who replaced Olmert as head of the centrist Kadima party and is running to replace him as prime minister, said she was committed to continuing the negotiations.

"It is important that we preserve the process," Livni said with Rice at her side. "I believe deeply that stagnation is not in Israel's interest and it cannot be our policy."

But polls show Livni is locked in a close race with the right-wing Likud party of former prime minister Benjamin Netanyahu, an outspoken critic of Olmert's peace proposals.

The last round of U.S.-backed peace talks collapsed in 2000 amid violence.

Rice will meet Abbas and other Palestinian leaders in the West Bank city of Ramallah on Friday.

She will also become the first U.S. secretary of state to visit the West Bank city of Jenin, where Abbas has deployed security forces as part of a U.S.-backed campaign to help persuade Israel that it can end its occupation without compromising its security.

On Saturday, Rice will travel to the Egyptian Red Sea resort of Sharm el-Sheikh, where the Quartet of Middle East peace mediators -- the European Union, Russia, the United Nations and the United States -- will be briefed by both sides.