Israeli Prime Minister Ariel Sharon (search), giving in to opposition from hard-line members of his government, said Tuesday he would ask his Likud Party to approve his proposal to withdraw from the Gaza Strip.

The announcement, made at a party convention, was a risky move for the prime minister, who has invested much of his political capital among Israelis -- and in Washington -- on his so-called "disengagement plan."

A "no" vote at a time when Sharon is also under investigation for alleged corruption would leave him politically vulnerable. A "yes" vote, on the other hand, could be the final blow to hard-liners in Likud (searchwho oppose territorial concessions and have been sniping at the prime minister. Sharon pledged he would abide by the outcome of the vote.

After conducting opinion polls recently, Sharon feels confident the 200,000 members of the party will back him, Israeli media said.

Meanwhile, a Palestinian militant group with ties to Yasser Arafat's Fatah (search) movement warned U.S. envoys not to visit the Palestinian territories, although some activists later backed down from the veiled threats. The development illustrated growing Palestinian hostility toward Washington, as well as divisions among Palestinians about how far to push the Americans.

Sharon has proposed unilaterally evacuating most or all Gaza Strip (searchsettlements and some West Bank communities if peacemaking with the Palestinians remains frozen. He told the convention his proposal is aimed at improving Israeli security.

"Because there is no partner on the Palestinian side, we must make difficult decisions in the near future," he said. "I will bring these things to a democratic test. ... The referendum will obligate all leaders of the Likud, and me among them."

Likud officials said the vote could take place in May, after Sharon returns from Washington, where he is scheduled to discuss his withdrawal plan with President Bush on April 14. The United States has so far refused to support the plan, requesting more details.

Early Wednesday, Israeli soldiers destroyed a small unauthorized settlement outpost called "Hazon David" near Hebron in the southern West Bank, Israel Radio reported. The outpost was made up of a tent and a shack used as a synagogue.

"With agony and sadness we announce that the army, under the orders of Sharon and (Defense Minister Shaul) Mofaz, has destroyed a synagogue," said Zvi Katsover, mayor of the nearby settlement of Kiryat Arba.

The U.S. envoys are to arrive Wednesday to hear more about the plan.

On Tuesday, the sponsors of the stalled "road map" peace plan met in Brussels to discuss reviving the plan, diplomatic sources said. Representatives of the mediators -- the United States, European Union, United Nations and Russia -- expressed qualified support for Sharon's Gaza plan, as long as it leads to further pullbacks and is in keeping with the road map blueprint, the sources said.

While no formal decisions were made at the meeting, the source said the talks signified renewed involvement by the sponsors of the road map, which aims to establish peace between Israel and an independent Palestinian state by 2005.

The Al Aqsa Martyrs' Brigades, a violent group linked to Arafat's Fatah, issued a statement Tuesday saying the U.S. delegation was banned from Palestinian territories. It also accused America of unfairly preventing the U.N. Security Council from condemning Israel's assassination of Hamas founder Sheik Ahmed Yassin last week, by vetoing a resolution.

"This visit is rejected completely, and the American administration will not like the circumstances of such a visit," it said.

Al Aqsa militants later softened the statement. Some said it had not been approved by members in the West Bank, and a leader in the Gaza Strip said there were no plans to harm the diplomats. "We have one enemy and that's enough," said Abu Qusay, the Gaza leader.

However, he said the Americans are not welcome in the Palestinian areas.

U.S. Embassy spokesman Paul Patin said he did not think the American delegation planned to enter the West Bank or Gaza, but "clearly our security people will be interested in this (threat)." Last October, a roadside bombing in Gaza killed three American guards in a diplomatic convoy.

The Al Aqsa statement reflected the growing Palestinian hostility toward the United States, which they have long accused of being biased toward Israel. The Yassin killing and the U.S. veto have only added to Palestinian anger.

However, the Palestinians are wary of open confrontation with the United States. Even Hamas, an extremist Islamic group, last week backed off anti-American threats made in the hours after Yassin's killing, saying its activities were confined to Israel and the Palestinian areas.

Palestinians have also grown divided over the violence in the current conflict, which began in September 2000 and has claimed thousands of lives.

On Tuesday, a group of prominent Palestinians distributed a leaflet saying violence against Israel is justified as long as Palestinian land is occupied. Organizers said it was a response to a newspaper ad last week by Palestinian intellectuals and moderates urging nonviolent resistance.

Palestinian legislator Hanan Ashrawi, who signed last week's ad, said it's hard to rally support for peaceful resistance when Israeli military action continues.

"Tempers are running high," she said. "Only when feelings calm down and emotions don't rule the day, people will be able to consider nonviolent resistance."