Postponing a showdown, the Palestinian parliament speaker temporarily blocked a confidence vote Wednesday that was sought by Prime Minister Mahmoud Abbas (searchin his power struggle with Yasser Arafat (search).

If a vote is held in the coming days, the U.S.-backed Abbas could be toppled, dealing a heavy blow to efforts to end three years of violence and move toward Palestinian statehood. The prime minister has minimal support among Palestinians, many of whom say they distrust him because he has Israel's backing.

Abbas is to address parliament Thursday to sum up his first 100 days in office, a period marked by somewhat reduced violence but also disappointment over a lack of movement in implementing the U.S.-backed "road map" peace plan.

Abbas' report will be debated, but legislators said a confidence vote is not expected for at least another week. In the meantime, parliament will try to help end the wrangling between Arafat and Abbas over their authority, particularly control of the security forces.

Israel has warned of dire consequences should Abbas be ousted, saying it won't do business with a government hand-picked by Arafat. Several Palestinian legislators said they were told by local U.S. diplomats that with Abbas gone, Washington might lower its profile as Mideast mediator.

Secretary of State Colin Powell (search), meanwhile, said in Washington that Arafat -- whom the U.S. and Israel have sought to isolate -- "has not been playing a helpful role."

"If he wanted to play a helpful role he would be supporting Prime Minister Abbas, not frustrating his efforts," Powell said.

Abbas has told a senior Palestinian official he wants Thursday's debate to be followed by a confidence vote but has not made a formal request. Abbas has declined public comment, spending most of Wednesday sequestered at his office.

Winning parliament's support would help Abbas in his confrontation with Arafat, who is accused by Israel of fomenting terrorism. Defeat would allow him to step down without being blamed for the consequences, such as the possible collapse of the road map.

The ongoing deadlock indicates that each man needs the other. The international support enjoyed by Abbas helps shield Arafat from possible Israeli action, such as expulsion. Abbas, in turn, needs Arafat to provide legitimacy for his government among Palestinians.

"They depend on each other, kind of like an old couple that can't stand each other, but can't live apart," said Israeli analyst Mark Heller.

Palestinian Parliament Speaker Ahmed Qureia said Wednesday that parliament should not be dragged into the Arafat-Abbas struggle. "Parliament will not accept being turned into a place of conflict or to be part of the current crisis," Qureia said.

The speaker said there is no need, for now, to hold a confidence vote in parliament because Abbas already won the legislators' confidence when his appointment was affirmed in April.

However, parliament will hold another session Sept. 10, and if Arafat and Abbas have not reached a power-sharing agreement by then, a confidence vote might be held, legislators said.

The power struggle between Abbas and Arafat has intensified in recent weeks.

Abbas, with the backing of the United States and Israel, demands that Arafat relinquish control of four security branches; Abbas commands the other four security services. Arafat has balked, fearing he would lose his main source of power.

State Department spokesman Richard Boucher said Powell "has made clear that Arafat is part of the problem at this point and is not helping to bring a solution."

Still, Boucher said Israel had informed the U.S. government there was no plan to expel Arafat and "our view was that was the right decision."

Israel and the United States want Abbas to crack down on Hamas and other militant groups, as required by the road map. Israel's Cabinet decided earlier this week to freeze implementation of the road map until Abbas orders a clampdown.

Abbas has been outspoken in his criticism of the militants' anti-Israel violence. But although he and his security chief, Mohammed Dahlan, have taken some measures, including freezing the bank accounts of Islamic charities with alleged links to Hamas, it remains unclear whether they would order a full crackdown even if given control of all security services.

Ahead of the parliament session, Israel sent strong warnings to the Palestinians.

Israeli Foreign Minister Silvan Shalom said Israel won't negotiate with an Arafat-controlled government, and Defense Minister Shaul Mofaz warned Tuesday that Israel may have to expel Arafat soon if he keeps getting in the way of the road map.

Mofaz spoke several days after Israeli security officials again reviewed a possible expulsion, and came to the conclusion that it would do more harm than good. Over the weekend, Israel's vice premier, Ehud Olmert, said another option is to isolate Arafat at his headquarters in the West Bank town of Ramallah, as Israel has done in the past.

Israel Army Radio reported that the United States has asked Israel for a clarification following Mofaz's expulsion comments.

An official at the U.S. Embassy in Tel Aviv, speaking on condition of anonymity, said Arafat is considered "part of the problem, not the solution," but that Washington does not want him expelled.

Several Palestinian legislators said privately that U.S. diplomats have cautioned them against ousting Abbas.

Chuck Hunter, a spokesman for the U.S. consulate in Jerusalem, declined comment on whether phone calls have been placed to Palestinian legislators. "Having said that, Abu Mazen (Abbas) is someone the (U.S.) president can work with and looks forward to continuing to work with," Hunter said.