Abbas' announcement follows months of failed attempts by the United States to restart direct peace talks between Israel and the Palestinians. A weekend trip to the region by Secretary of State Hillary Rodham Clinton accentuated the impasse, as the United States announced it was scaling back its expectations, and Palestinians contended there was a growing pro-Israeli tilt to U.S. policy.

Abbas' 15-minute address on Palestinian television remained equivocal as to whether he actually intends to leave office in a matter of weeks. Such a move would throw an already-chaotic Palestinian political system into full disarray. But advisers and analysts said it was possible he was merely venting frustration over a dialogue with the United States and Israel that has undercut him politically without any marked progress toward the creation of a Palestinian state.

"I do not wish to run for the upcoming presidential elections," the 74-year-old leader said. "This decision is not for negotiation or maneuver."

With a list of detailed steps he thinks are needed to move peace talks forward, the speech seemed designed to leave options open while exerting pressure on Israel and the Obama administration. The address should "be understood as an urgent scream against the continuing pressure and bending our arms" by the United States and Israel, Abbas aide Yasser Abed Rabbo said immediately after the president spoke.

After initial optimism that President Obama's election would elevate Palestinian interests, Abbas has been steadily frustrated in his hopes for quick results on issues he regards as central, such as a freeze on the construction of Israeli settlements in the West Bank.

Instead, his political standing has declined, as decisions made in consultation with the United States proved unpopular locally while still failing to produce anticipated Israeli concessions.

"We are at a crossroads," Abbas said at the start of his speech. "Month after month and year after year we have seen nothing but complacency and procrastination." He added that he was particularly "surprised" in recent days when Clinton praised Israel for an offer on settlement construction that fell well short of Palestinian expectations.

Abbas warned that Arab anger over Israeli home demolitions in Jerusalem and recent clashes near the Al-Aqsa Mosque threatened a "religious war."

Clinton, asked about Abbas' decision, said that at a recent meeting "we talked about his own political future. I look forward to working with President Abbas in any new capacity."

A spokesman for Israeli Prime Minister Benjamin Netanyahu would not comment on the announcement.

Abbas' speech followed a day in which Palestinian officials and political organizations lobbied him to reconsider a decision he has been considering for at least several days. Abbas was given a strong endorsement yesterday by the PLO central committee, which "rejected" his possible retirement.

The chief advocate among Palestinians for a negotiated settlement with the Israelis, Abbas is the most prominent remaining member of the group that founded the PLO.

With no clear successors, his departure could spark a broader debate over whether Palestinians should pursue continued dialogue with Israel or return to the more violent methods advocated by groups such as the Islamist movement Hamas.

Among Palestinian leaders, Marwan Barghouti is considered the most popular and charismatic - but he is serving multiple life sentences in an Israeli prison for his role in organizing violent attacks as head of a Palestinian militia during the second intifadah.

U.N. Vote Backs Gaza Report; U.S. and Israel Vote No

The U.S. and Israel were joined yesterday at the United Nations by 16 other countries in opposing a call for further investigation of alleged war crimes during Israel's military offensive last winter in the Gaza Strip.

The U.N. General Assembly voted 114-18, with 44 abstentions, to adopt a resolution calling for Israeli and Palestinian authorities to begin probes within three months. The nonbinding resolution was drafted and introduced by the Palestinian Authority and most Arab nations.

The measure endorses

the report of a panel, led by former South African judge Richard Goldstone, that said Israel and Hamas both committed war crimes during the three-week conflict. It asks the U.N. Security Council to take "necessary action" if they don't comply; that could include referring the allegations to the International Criminal Court for prosecution.

U.S. Deputy Ambassador Alejandro Wolff said, "We believe the Goldstone report is deeply flawed, including its unbalanced focus on Israel." Israel says its operations in Gaza were a defensive response to eight years of rocket attacks by Hamas, which controls Gaza.

- Bloomberg News