Israeli and American officials expressed concern over Palestinian President Mahmoud Abbas's announcement on Thursday that he will not be running for reelection in January.

President Shimon Peres telephoned Abbas on Wednesday night in an effort to persuade the Palestinian leader to change his mind. Peres told Abbas that he was worried that the decision would trigger political crisis in the Palestinian Authority, leading to a Hamas takeover in the West Bank.

"If you leave the Palestinians would lose their chance for an independent state," Peres told Abbas. "The situation in the region would deteriorate. Stay, for the Palestinian people's sake," he said.

Aides to Benjamin Netanyahu refused to comment on Abbas' statement, but the prime minister has reportedly said in private meetings recently that it was in Israel's interest to have a strong Abbas who could advance the peace process. Netanyahu made similar statements to U.S. Secretary of State Hillary Clinton a week ago, saying that it was in Israel's interest to strengthen Abbas as much as possible.

"Of the existing alternatives, if we want an agreement with the Palestinians then Abbas is the best partner," Netanyahu said a few days ago.

He said he was serious about the peace process with the Palestinians and was ready to take risks to advance peace, despite the PA leadership's impression to the contrary.

"The best partner is Abbas, but any Israeli intervention in internal Palestinian politics would only do harm," Netanyahu said. Defense Minister Ehud Barak added that he hoped Abbas' reluctance to run for reelection would not damage the attempt to resume the peace process.

"It's important for both sides to adhere to the principle of negotiating to advance an arrangement," Barak said in a statement. "I suggest making every effort to reach a two-state-for-two-peoples arrangement, while preserving Israel's security interests," he said.

A senior U.S. official, speaking anonymously about the possibility of Abbas disappearing from the political scene, said, "There's a real crisis situation in the PA." Clinton asked Egyptian President Hosni Mubarak on Wednesday and Arab foreign ministers she met in Morocco two days earlier to urge Abbas to remain in office and run for reelection.