The Palestinian parliament could vote Prime Minister Mahmoud Abbas (search) from power unless he wins substantial Israeli concessions in upcoming talks in Washington, a top Palestinian official said Wednesday.

Abbas, who is supported by the United States and Israel but lacks popularity among Palestinians, is under heavy pressure to make progress in talks on Friday with President Bush.

The Palestinians want Bush to press Israel to release thousands of Palestinian prisoners, stop construction of settlements on the West Bank (search) and Gaza Strip (search), and take other steps.

If Abbas "is unable to achieve any progress on these ... points, we are sure that he will face difficulties on the Palestinian street and inside the [legislature]," Information Minister Nabil Amr said.

Amr said the parliament would convene when Abbas returns from Washington to assess his progress and "discuss again giving him its confidence or not."

Israel and the United States are interested in keeping Abbas in power, since they supported his appointment in April and see him as a replacement for Palestinian leader Yasser Arafat (search), whom they accuse of encouraging violence.

A temporary truce by the main militant groups on June 29 has greatly diminished the violence of the previous 33 months, but progress has stalled on the U.S.-backed "road map" peace plan that would lead to a Palestinian state by 2005. The militants have also threatened to abandon the truce unless prisoners are released.

Bush is to meet with Israeli Prime Minister Ariel Sharon on July 29, and both Israel and the Palestinians are hoping Bush will break the deadlock.

Israel has refused so far to meet Palestinian demands until Abbas' government begins disarming militant groups that have killed hundreds of Israelis. The Palestinians, however, fear a confrontation with militants would lead to civil war and prefer to disarm them through negotiation.

The release of prisoners has emerged as a key Palestinian demand. Israel holds about 7,700 Palestinians in jail, but has only agreed to release several hundred.

On Wednesday, Israeli Foreign Ministry spokesman Yonatan Peled said the first prisoners would be released within days.

Peled said Israel had a list of about 400 candidates for imminent release, "and we are confident that these prisoners will be released within a week, maybe in one single move or maybe in two steps."

He did not say whether any of those freed would be from the Islamic militant groups Hamas or Islamic Jihad. Freeing some from these groups would boost to Abbas, who wants them to maintain their truce.

Peled said Israel would consider releasing prisoners who had not been implicated in violence, "regardless of their political or terrorist organization affiliation."

A committee of Israeli government ministers met Wednesday to discuss the releases, but deferred a decision on whether to free members of Hamas and Islamic Jihad until another discussion of the issue in the full Cabinet.

A government statement said Sharon had told the committee prisoner releases would be made in small batches, and "weighed against decisive Palestinian action in the security field."

Labor and welfare minister Zevulon Orlev, a committee member from the hawkish National Religious Party, said releasing Hamas and Islamic Jihad militants would be "very difficult morally, a grave political mistake and a very dangerous security gamble."

But Israel Radio quoted the Shin Bet security agency as saying its chief, Avi Dichter, had told ministers the release of some members of those groups had already been agreed.

Hamas spokesman Abdel Aziz Rantisi repeated his insistence that the prisoner issue "is a red line for all the Palestinians."

Palestinian Minister of Security Affairs Mohammed Dahlan condemned the Israeli government's move to defer a decision on releasing prisoners affiliated with Hamas and Islamic Jihad.

"Israel is once again trying to impose on the Palestinians its own logic and diktat with regard to defining the names and numbers of prisoners to be released from Israeli jails," he said in a statement.

Dahlan also said that Jordanian King Abdullah II agreed in talks in Amman this week to ease restrictions on Palestinians crossing the Allenby Bridge between Jordan and the West Bank.

Jordan placed new restrictions on Palestinians crossing the bridge in June 2002 fearing that many would seek to stay there to escape Israeli military action in parts of the West Bank.

In other developments Wednesday:

-- The army said police had arrested two Palestinians overnight in the northern West Bank village of Rai. The army said the men were Islamic Jihad members planning a suicide bombing in Israel.

-- Military sources said that Palestinians fired two rockets from the northern Gaza Strip in the direction of Kibbutz Niram in southern Israel. The sources said they were uncertain if or where the rockets landed.

-- An Israeli was stabbed in the back by four Palestinian youths, but his wounds were not life-threatening, police spokesman Gil Kleiman said. He said that the attack happened near the Shuafat refugee camp north of Jerusalem, and police were searching for the assailants.