Ceasefire collapses as Israel kills Hamas leader

A senior Hamas official was killed in an Israeli gunship attack in Gaza City today, in retaliation for Tuesday's suicide bus bombing in Jerusalem in which 20 people died, including six children.

Islamic militants threatened revenge and formally called off a ceasefire declared eight weeks ago.

Palestinian Prime Minister Abu Mazen warned that the assassination of Ismail Abu Shanab would make it harder to crack down on militant groups, and a Palestinian official said the campaign to control the groups was now on hold.

Under pressure from Washington and Israel, the Palestinian leadership had decided on a clampdown last night, just hours before the missile strike.

"The end of the road map is a cliff that both sides will fall off of," US Secretary of State Colin Powell said today.

Abu Shanab was in his estate car, with two bodyguards, when the vehicle was hit by five missiles fired from an Israeli helicopter. The car burst into flames and three bodies were pulled from the wreckage.

Fifteen bystanders were hurt. Dozens of Hamas supporters put their fists in blood and soot, raised them in the air and threatened revenge, chanting "God is great."

Abu Shanab, who had a degree in civil engineering from the University of Colorado, was widely regarded as a moderate in Hamas, and served as a liaison with Mr Mazen during the prime minister's efforts to persuade militants to halt attacks.

Abu Shanab, who was in his early 50s, was the third member of Hamas' political wing to be killed in targeted Israeli attacks in the past two years.

Israel has routinely targeted members of Hamas' military wing, but has rarely gone after the political leaders.

The Israeli military confirmed it killed him, and said he was involved in the planning of attacks, along with other Hamas leaders. "There's no question that there is a direct link between the heads of Hamas and the terrorists on the ground," said Israeli Foreign Ministry official Gideon Meir.

Hamas and Islamic Jihad, formally called off the unilateral ceasefire they declared 29 June.

"We consider ourselves no longer bound by this cease-fire," said a Hamas leader, Ismail Hanieh, after identifying Abu Shanab's decapitated body at a Gaza City mortuary.

The Hamas founder and spiritual of Hamas, Sheik Ahmed Yassin, said his group would take revenge. "This crosses all red lines," Yassin said of the missile strike. Addressing the Israelis, he said: "You will pay the price for these crimes."

The truce had been a result of negotiations between the militant groups and Abbas who wanted to avoid a violent confrontation with them.

In New York, Mr Powell said that "both sides should recommit themselves to finding a way forward."

He called for international pressure to end Palestinian attacks, and urged Yasser Arafat to give Mr Mazen more control of Palestinian security forces.

"It has to end. The Palestinian people, the Israeli people, deserve better. And those who are determined to blow up the road map must not be allowed to succeed," Mr Powell said after talks with UN Secretary General Kofi Annan in New York.

The Israeli security Cabinet decided last night to renew the campaign of targeted killings, in response to the Jerusalem bombing, the deadliest since the launch of the road map three months ago. More than 100 people were wounded in the blast, including about 40 children.

After the Jerusalem bombing, Mr Mazen had ordered the arrest of all those directly involved in the attack, and then asked his Cabinet for proposals on a wider clampdown. The ideas raised in the Cabinet included arrests, a gag order on Hamas and Islamic Jihad spokesmen and the freezing of assets of militant groups.

Israeli troops, meanwhile, raided the West Bank towns of Nablus, Jenin and Tulkarem in search of militants.

The biggest operation was carried out in the old city of Nablus, a militant stronghold where troops were looking for Hamas militants and Fatah renegades responsible for two bombings that killed two Israelis earlier this month.

Troops sealed off the old city with armored vehicles and barbed wire and ordered residents out of homes to search buildings. Soldiers took over several buildings as outposts, suggesting a longer stay. They arrested 14 Palestinians in and around Nablus during the night, including a Hamas member caught with a large quantity of explosives, the army and witnesses said.

In the town of Tulkarem, Israeli undercover troops chasing two Fatah gunmen raided a local pool hall, but the fugitives managed to escaped. The soldiers opened fire during the chase, killing a 16-year-old bystander and wounding four, all under the age of 20, Palestinian security officials said. The Israeli military said there was a gunbattle.

A third raid targeted the town of Jenin and an adjacent refugee camp, a stronghold of the Al Aqsa Martyrs' Brigade, a militant group loosely linked to Fatah. No arrests were made.

In the West Bank city Hebron, troops blew up the home of the Jerusalem bus bomber, a routine punishment intended as deterrent.