Palestinian Prime Minister Mahmoud Abbas, weakened by a power struggle with Yasser Arafat, yesterday asked parliament to back him, saying that otherwise no progress can be made on a US -backed peace plan.

In his speech to parliament, Abbas said there were ?problems? between his government and the Palestinian leadership, although he did not mention Arafat by name.

Abbas hinted at resignation if he did not win support, saying he would not put up a fight to keep his job, which he described as a ?difficult mission that some would say is impossible.?

Just before the session, Palestinian gunmen killed an Israeli in a shooting ambush near the West Bank town of Jenin. The Al Aqsa Martyrs? Brigade, an armed group linked to Arafat?s ruling Fatah movement claimed responsibility.

In an angry demonstration outside the parliament building earlier yesterday, about 200 Fatah activists promised to defend Arafat, and seven masked men from the crowd broke down a door to the building and smashed windows. Unarmed guards eventually forced the men out.

Abbas said the disputes among Palestinians leaders are not a personal issue, but part of an underlying problem.

?For without the oneness of authority and without the unity of decision-making and without an absolute enforcement of law on all, and without a legitimate force in the hands of one authority and without political pluralism, we will not advance one step on the political track,? he said, referring to the ?road map? peace plan.

The Prime Minister told legislators it was up to them to create these conditions.

?You either provide the resources of power and support those things ... or you take it back,? he said, but stopped short of demanding a vote of confidence in yesterday?s session.

Abbas was summing 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.

A cease-fire declared June 29 by militant groups collapsed after a Hamas suicide bombing in mid-August killed 21 people on a Jerusalem bus.

Abbas told lawmakers he would continue talks with militants rather than launching a campaign to disarm and dismantle their groups.

?This government does not deal with the opposition groups with the policing mentality, but the mentality of dialogue,? he said.

The parliament speaker, Ahmed Qureia, has temporarily blocked a confidence vote Abbas had wanted to follow his address.

Qureia said parliament shouldn?t be dragged into the struggle between Abbas and Arafat, who have been arguing over job definition and control over security forces. However, a vote might be held next week, if mediation efforts fail.

Abbas was reluctantly appointed by Arafat as the Palestinians? first prime minister in April under pressure from Israel and the United States, which have accused Arafat of blocking peace efforts.

But he has minimal support among Palestinians and could be toppled, dealing a heavy blow to efforts to end three years of violence and move toward Palestinian statehood.

On Wednesday, Secretary of State Colin Powell 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.

Israel has warned of dire consequences should Abbas be ousted, saying it will not do business with a government hand-picked by Arafat. Several Palestinian legislators said they were told by local US diplomats that if Abbas is ousted, Washington might lower its profile as Mideast mediator.

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 continued deadlock indicates each man needs the other. The international support enjoyed by Abbas helps shield Arafat from possible Israeli action, like 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,? Israeli analyst Mark Heller said.

Parliament will hold another session next Wednesday, and if Arafat and Abbas have not reached a power-sharing agreement by then, a confidence vote might be held, legislators said.

Lara SUKHTIAN