HEBRON, West Bank ? Palestinian militants raked Israeli troops and settlers with massive gunfire Friday in a carefully orchestrated ambush, killing 12 Israelis and wounding 15 in Hebron, a divided city long plagued by religious tensions and flashes of furious violence.

The Israelis were emerging from Sabbath prayers in the Tomb of the Patriarchs, a shrine in downtown Hebron, and were walking along “worshippers’ lane” when Palestinians fired assault rifles and hurled grenades from the hilltop Abu Sneineh neighborhood, army sources said.

A nearby army post and solders rushing to the scene were also caught in the ambush, the sources said.

“There was gunfire from left and right, from every possible angle, they were shooting at us from above,” one man, who gave hisz name only as Arik, told Army Radio. “The group of Jews were slaughtered.”

Gun battles raged for more than 90 minutes, making it difficult for troops to reach the wounded. Flares lit up the night sky and military helicopters helped evacuate the wounded, including the regional brigade commander ” a colonel ” and members of his entourage.

Troops hunted for the gunmen, and TV reports said a gun battle erupted as soldiers surrounded a Palestinian home.

The militant Islamic Jihad group claimed responsibility, saying it was avenging the killing of its northern West Bank commander, Iyad Sawalha, by Israeli troops several days ago.

Explosive violence in Hebron can have wider implications. The city is a tinderbox of tension where politics meets religion. The Muslims here are among the most devout and the Jewish settlers among the most radical, and there are daily provocations and practically no neighborly relations between the two sides.

An Israeli border policeman secures the area around the Tomb of the Patriarchs, background, as Jewish pilgrims walk by in the southern West Bank town of Hebron in this Nov. 10, 2001, file photo. Palestinian militants opened fire on Israeli settlers and soldiers walking near the Tomb, a shrine revered by both Muslims and Jews, on Friday, killing 12 and wounding 15, the military said.

Hours later Israeli military helicopters fired missiles into Gaza City, hitting a metal workshop in a congested area, witnesses said. The army said it was used by Palestinian militants to manufacture weapons. No injuries were reported.

Both attacks come five days after a Palestinian gunman killed five people, including two small boys, on an Israeli kibbutz. Friday’s attack, the deadliest since 14 were killed by a car bomb Oct. 21, and it was sure to increase pressure on Prime Minister Ariel Sharon to respond decisively.

One idea that could arise again is the expulsion of Palestinian leader Yasser Arafat ” which Israel’s new foreign minister, Benjamin Netanyahu, has been strongly advocating.