Four more die as the tension rises on West Bank

Four Palestinians were killed yesterday, one in a helicopter strike, two in a mysterious blast and the fourth in a clash with Israeli soldiers, while refugees built fortifications to fend off a feared Israeli invasion in a West Bank camp, a stronghold of militant gunmen.

Four Palestinians were killed yesterday, one in a helicopter strike, two in a mysterious blast and the fourth in a clash with Israeli soldiers, while refugees built fortifications to fend off a feared Israeli invasion in a West Bank camp, a stronghold of militant gunmen.

Tension ran high as analysts on both sides predicted a continuing surge of violence. Because of the flare-up, American officials put on hold efforts by the envoy Anthony Zinni to mediate a truce.

In Gaza after nightfall, witnesses said an Israeli helicopter fired missiles at a car, killing one Palestinian and wounding two others. Palestinians said the three were members of Hamas.

Earlier in Gaza, the mangled bodies of two Palestinians were found after daybreak. The militant Popular Front for the Liberation of Palestine said the two were killed in a "heroic martyrs' operation". Israeli radio said it was apparently a failed suicide bomb attack against a Jewish settlement.

In the West Bank town of Ramallah, a Palestinian intelligence officer was killed in a clash with Israeli forces. Israeli tanks are parked there about 70 metres from the headquarters of the Palestinian leader, Yasser Arafat, holding him under virtual house arrest for the past two months.

In Gaza, about 1,500 Palestinians marched in support of Mr Arafat yesterday. "We are protesting [Ariel] Sharon's crimes against our people and against our beloved president," said a law student, Rami Abu Safiya, 24.

In Jenin, a militants' strong-hold at the northern edge of the West Bank, Palestinians are expecting an Israeli incursion. About 300 militants armed with rifles and hand grenades have moved from the town into a nearby refugee camp, and are building earth ramparts up to 3m (10ft) high across roads to keep out the Israelis.