Hounded by his moderate supporters and militant rivals alike, Palestinian Authority President Mahmoud Abbas is facing a leadership crisis that will make it harder for the Obama administration to draw him into peace talks with Israel.

For months, Abbas enjoyed broad Palestinian support for his refusal to meet with the Israelis unless they stopped expanding Jewish settlements in the West Bank. Then he made two concessions that ignited fury at home and across the Arab world:

First he joined President Obama and Israeli Prime Minister Benjamin Netanyahu for a meeting in New York last month to explore prospects for formal talks. Then last week he agreed, under American pressure, to postpone the Palestinians' demand for a United Nations Security Council debate on a U.N. report accusing Israel of war crimes in the Gaza Strip.

The United States and Israel had warned the Palestinians that pursuing the accusations now would thwart attempts to revive a peace process. But the outcry against Abbas appears to be having the same effect.

When he meets today with U.S. envoy George J. Mitchell, Abbas will do so under intensifying pressure from his Fatah movement to stand by conditions that Israel rejects: a settlement freeze and a commitment to negotiate all issues of the Middle East conflict.

Moving to limit the damage, the Palestinian leadership Wednesday reversed its decision on the war crimes debate and joined Arab nations in calling for the Security Council to take it up next week.

The shift came a day after hundreds of Palestinians demonstrated in Ramallah, the West Bank seat of Abbas' government, and called for his resignation. In Gaza, run by the rival Hamas movement, protesters threw shoes at posters depicting the 74-year-old Palestinian leader and branding him a traitor.

The Obama administration's push for peace talks is also under attack in Israel. As Mitchell began a round of meetings here Thursday, Foreign Minister Avigdor Lieberman declared in a radio interview that there is no chance of reaching a final accord with the Palestinians for many years.

"Whoever says it's possible . . . simply doesn't understand reality and spreads delusions, ultimately leading to disappointments and all-out confrontation," Lieberman said.

Entering a meeting with Israeli President Shimon Peres, Mitchell said that firm positions on both sides were to be expected. But resuming the Israeli-Palestinian talks is essential, he said, for a comprehensive treaty creating a Palestinian state and ending conflicts between Israel and its Syrian and Lebanese neighbors.

"There is no alternative if the people of the region are to live in peace," Mitchell said.

Israeli Prime Minister Benjamin Netanyahu has for months offered to resume the talks, with no set agenda. They were suspended in December at the start of Israel's 22-day military offensive in Gaza, three months before Netanyahu's conservative-led government was sworn in.

The Israeli leader has resisted pressure from Washington to halt settlement growth, a step Obama hoped would induce Arab concessions to Israel. The construction of hundreds of apartments for Jews on land claimed by the Palestinians must continue, Netanyahu insisted, in order to accommodate "natural growth" of communities Israel expects to keep when borders of a new Palestinian state are drawn.

Obama shifted tactics last month and pressed Abbas to restart the talks without a settlement freeze.

The criticism heaped on Abbas merely for meeting with Netanyahu mounted after his initial decision to delay the U.N. war crimes debate, a step that seemed to deprive the Palestinians of a diplomatic weapon against Israel. The U.N. report found evidence that both Israel and Gaza militants took actions amounting to war crimes last winter, but it focused far more criticism on Israel.

"The two decisions have cost Abbas tremendously," said Hani Masri, a columnist close to Fatah. "I have never seen him so weakened and humiliated."

Abbas has said little but promised to explain his actions in a speech.

He is under pressure on several fronts. Hamas, which shuns the goal of a peace accord with Israel, is attacking Abbas as soft and vacillating on the war crimes issue, a theme it could exploit as he seeks reelection in a vote tentatively set for next year.

In addition, Islamic militants sympathetic to Hamas have been leading protests against what they call attempts by right-wing Jewish groups to pray outside Al Aqsa mosque in Jerusalem's Old City.

Israel has accused the Palestinians of stirring up trouble and has restricted access this week to the mosque and surrounding site, which is holy to Muslims and Jews. The tensions have led to sporadic rock-throwing protests by Arabs in East Jerusalem and put Abbas' government in the awkward position of a powerless spectator.

Under the circumstances, said Mouin Rabbani, a Palestinian political analyst based in Jordan, "I cannot imagine that Abbas can meet Mitchell and simply agree to resume negotiations with Israel without preconditions, as Obama seems to want."

"I find it even more difficult to believe that if Abbas does so, the Fatah leadership will take it lying down," he said. "The knives will come out."