The aftermath of Saturday's Jenin raid

His trip comes amid increasing international concern over the escalating conflict between Israel and the Palestinians.

On Sunday, the Palestinian authorities released from detention a senior figure in the militant group, Hamas.

Abdel Aziz Rantissi was arrested two weeks ago at a rally in the Gaza Strip after brandishing an AK-47 rifle and condemning any idea of a ceasefire with Israel.

The release comes at a sensitive time. On Tuesday, Palestinians will mark Al Nakba Day, the anniversary of the creation of the Israeli state in 1948, which they describe as a "catastrophe".

On Saturday night, a Palestinian man is reported to have been killed and at least seven others injured during clashes between the Israeli army and Palestinian gunmen in the Gaza Strip on Saturday night.

"Very fine report"

Commenting on the Washington mission, a Palestinian official told voice of Palestine Radio: "The goal of the meetings is to look at ways to get out of the crisis."

Mr Abbas is due to discuss with US Secretary of State Colin Powell a report by an international panel which calls for Israel to freeze the expansion of Jewish settlments in the West Bank and Gaza Strip.

If somebody comes to kill you, rise early and kill him first

Matan Vilnai Israeli minister

Mr Powell has described the report as "very fine", saying it could "give us a launch pad to start a new initiative" in the Middle East.

But Israeli Prime Minister Ariel Sharon has already rejected any freeze on settlements.

The talks are also expected to explore an Egyptian-Jordanian plan that would lead to a full resumption of peace talks.

Army denial

Saturday night's killing capped another violent day in the region.

Sharon has rejected a freeze on settlements

The Israeli defence force says its soldiers returned fire after coming under near continuous gunfire for about two hours from a Palestinian police position near the Maghazi refugee camp.

Earlier in the day, two Palestinians were killed in the West Bank town of Jenin when Israeli helicopter fired missiles at a car parked near the security headquarters of the Palestinian Authority.

One of those who died was a senior member of Yasser Arafat's Fatah movement. The other was a Palestinian policeman who was standing nearby at the time.

Israeli army chief General Shaul Mofaz denied he was trying to destroy the Palestinian Authority.

"The army's objective is... to signal that [the Palestinian Authority] must stop the violence," Israel radio reported him as saying on Sunday.

Pope John Paul II denounced the "immoral chain of provocations and reprisals" in an address to worshippers in Rome on Sunday.