Israel said it was acting on information that more attacks were planned by Palestinians following the killing of four Israelis at the nearby settlement of Adora on Saturday.

Israeli tanks briefly entered Hebron several days ago, but the town has been one of the few in the West Bank to have largely avoided the military offensive of the past month.

The latest incursion came just hours after Israel and the Palestinians accepted a US plan to allow the Palestinian leader, Yasser Arafat, to leave his besieged compound in Ramallah.

Arrests

Palestinian security sources said that tanks and armoured vehicles backed by helicopters entered Hebron before dawn and imposed a curfew.

They said that one of those killed was an activist in the militant group, the al-Aqsa Martyrs' Brigade, three were policemen and the other three unarmed civilians. About 20 people had been injured.

Witnesses said soldiers were conducting house-to-house searches and making arrests.

Israeli military sources said 10 Palestinian militants had been arrested, including two Hamas activists.

Siege deal struck

Under the US plan to end the stand-off in Ramallah, Israeli forces will pull back from Mr Arafat's compound and leave him free to travel, once six Palestinian men wanted by Israel are moved to a Palestinian prison where they will be held by US and British guards.

Four of the men were sentenced at a court hearing on Thursday

Four of the six Palestinian detainees were convicted of the killing of Israeli cabinet minister Rehavam Zeevi at a makeshift trial at Mr Arafat's compound on Thursday and sentenced to long jail terms.

Under the plan, the men will remain in an area under Palestinian control, but will be supervised by the US and British guards.

American and British security officers are due to arrive in the Palestinian territories on Monday to assess the technical details.

Israeli tanks encircled Mr Arafat's compound on 29 March as part of a West Bank offensive launched after Palestinian suicide attacks killed scores of Israelis.

US President George W Bush called on Mr Arafat to show leadership, after the deal was agreed.

"Mr Arafat must perform," said Mr Bush. "He must earn my respect by leading."

Speaking on what he called "a hopeful day for the region", President Bush said all parties must "step up to their responsibilities".

After the plan to lift the Ramallah siege was announced, White House officials said that Israeli Prime Minister Ariel Sharon would visit the US in the next 10 days for talks with Mr Bush.

Jenin delay

The United Nations Security Council has given Israel another day to accept a UN fact-finding mission to the Palestinian refugee camp in Jenin.

The UN team was to investigate events at the Jenin refugee camp

The council did not adopt a new resolution forcing Israel to accept the team, but it did strongly back Secretary General Kofi Annan's efforts to win Israeli backing.

The Palestinians say hundreds of people were killed during the Israeli incursion into Jenin.

Israel acknowledges only dozens of casualties in what it describes as a legitimate operation to root out militants.

The Israeli Government has already delayed the UN team's arrival twice with objections about its make-up and mandate, and a cabinet meeting on Sunday refused to allow it to go ahead.

The cabinet is due to meet again on Monday to discuss the issue.

Bethlehem talks

The Archbishop of Canterbury's representative to the Middle East has told the BBC that significant progress was made on Sunday evening in talks aimed at ending the stand-off at the Church of the Nativity in Bethlehem.

About 200 armed Palestinians are holed up in the church, including 30 suspected militants wanted by Israel.

Canon Andrew White said agreement was expected soon to allow several dozen Palestinian civilians to leave the church and for food to be delivered to those left inside.