Israeli soldiers patrolling the West Bank city of Nablus (search) shot and killed three Palestinians during fighting Saturday that spilled over into the funeral procession later in the day, when troops killed a fourth Palestinian.

The killings threatened to undermine a renewed Egyptian initiative to negotiate a cease-fire after 39 months of Mideast violence.

The cause of the violence in Nablus was disputed. The Israeli military said troops opened fire after being attacked with rocks, firebombs and a concrete block dropped from a roof. Palestinian witnesses said Israelis killed an attacker and two bystanders, including a 15-year-old boy on a rooftop watching troops pass.

Hours later, Israeli soldiers shot at Palestinians during the funeral procession for the three dead, killing one man and lightly wounding three others. The army said troops shot two armed men who walked in their direction during the gathering. Witnesses claimed the shooting was unprovoked.

Israeli soldiers usually give a wide berth to funeral processions, where mourners with rifles often shoot into the air. Witnesses said there were no gunmen at the funeral Saturday.

Chief Palestinian negotiator Saeb Erekat (search) criticized the killings, saying "we hold the Israeli government fully responsible for its consequences."

Over the past two weeks, Israel has conducted a series of raids in Nablus in an effort to weaken Palestinian militant groups operating in the area.

Late Friday, a roadside bomb blew up next to an Israeli army jeep in the West Bank city. The militant Islamic Jihad group took responsibility for the attack, which caused no casualties.

In other violence, Israeli forces shot and killed a Palestinian planting an explosive device near a Jewish settlement in the Gaza Strip (search) late Friday, the military said.

Nablus was quiet Saturday morning when the military said a patrol was ambushed from several different directions and heavy rocks were dropped on troops from the roof. The soldiers shot an attacker on the roof, the military said.

The soldiers also shot a Palestinian who was running toward them with a pistol and another who had just lit a firebomb and was preparing to throw it, the military said. Military sources could not confirm whether they had been killed.

Palestinian witnesses said Saturday's clashes began when troops shot Amjad al Masri, 15, as he sat on his roof watching the troops pass. As news spread of his killing, Palestinians began throwing stones and other objects at soldiers, witnesses said.

Troops later killed Amar Arafat, 19, who was attacking them, and Rohi Hazam Shoman, a 25-year-old bystander, witnesses said.

About two hours later at the funeral procession, troops shot at a crowd of about 2,000 Palestinians from about 200 yards away, hitting Amjad's relative Mohammed al Masri in the head and killing him, witnesses said. Three other men were lightly injured, they said.

Military sources said troops opened fire when two men came out of the crowd, one wielding a pistol and the other a fire bomb.

The violence came amid reports Egypt will send intelligence chief Gen. Omar Suleiman — a key Mideast mediator — to meet with Palestinians next week in a renewed effort to forge an agreement with militant groups to end attacks on Israel, Palestinian officials said Friday.

Palestinian Prime Minister Ahmed Qureia (search) has hoped such an agreement would help spur renewed efforts to implement the U.S.-backed "road map" peace plan, which envisions a Palestinian state by 2005.

Israeli Prime Minister Ariel Sharon (search) said last month that if there is no progress on the road map, he would unilaterally redraw the lines between Israel and the Palestinians.

While Sharon said his plan would include the removal of some Jewish settlements in the West Bank and Gaza, he said the Palestinians would receive far more land under a negotiated settlement.