Jerusalem ? Palestinian gunmen killed four Jewish settlers Friday in an ambush of two cars in the southern West Bank, Israeli authorities said. The dead included a couple and one of their children.

A militia affiliated with Palestinian leader Yasser Arafat’s Fatah movement reportedly claimed responsibility for the shootings south of the West Bank city of Hebron. All major militant Palestinian factions have vowed to avenge Israel’s killing earlier this week of 15 Gazans, including nine children and a Hamas military commander.

Palestinian women, members of the Hamas military, chant religious slogans as they hold the group's military commander Salah Shehadeh's picture and the Quran, during a march through the streets of the the Jabaliya refugee camp on the edge of Gaza City. Demonstrators Friday were protesting Tuesday's Israeli airstrikes that killed 15, including Shehadeh.

The dropping of a one-ton bomb on a congested Gaza City residential neighborhood which achieved its goal of killing the head of Hamas’ military wing, torpedoed a plan by several Palestinian factions to declare a cease-fire and suspend attacks after 22 months of Israeli-Palestinian fighting, according to Palestinian officials and Western diplomats.

Retaliation began quickly, with the killing Thursday of a rabbi from a Jewish settlement, and then Friday’s attack. People on both sides of this conflict fear a new surge in bloodshed.

Two or three gunmen opened fire on a white station wagon carrying a family of Jewish settlers en route to the settlement of Maon to spend the Sabbath, authorities said. The car’s occupants included a couple and their four children, whose names were not immediately released.

The two adults and one child, reported to be about 14, were killed and the other children including a 2-year-old-were injured.

The gunmen continued firing and hit a second car, killing another settler and wounding his companion. Israeli authorities said the gunmen apparently escaped into the Palestinian village of Yatta, where the army late Friday was searching for them.

Reacting to the attack, Israel accused the Palestinians of targeting civilians. “No people can be expected to tolerate this terror, and Israel will certainly not do so,” said a statement from the office of Prime Minister Ariel Sharon.

Settlers are frequent targets of Palestinian gunmen. Many militants consider them to be legitimate targets because they settle in land the Palestinians claim as their future state.

Earlier Friday, Israeli forces briefly invaded Gaza City and blew up two metalworks factories that the army said were being used to produce rockets that militants frequently fire on Jewish settlements in the Gaza Strip.

The owners of the two workshops denied military equipment was being fabricated at their businesses and said the destruction will throw dozens of already destitute Palestinians out of work.

Four Palestinians a woman and three men were injured in the raid and an ensuing firefight.

Also Friday, Israeli troops conducing house-to-house searches fatally shot a Palestinian man as he stood in his kitchen in the West Bank city of Kalkilya, according to Palestinian officials.