RAMALLAH ø Israeli forces killed leaders of three major Palestinian insurgency organizations Saturday in a house-to-house search.

Palestinian sources said an Israeli attack on a suspected insurgency stronghold in the northern West Bank city of Nablus killed eight people.

Israeli sources confirmed that the heads of Fatah, Hamas and Jihad were killed in the Israeli operation, Middle East Newsline reported. The sources identified the three as Fatah cell chief Nayef Abu Sharah, Hamas commander Jadi Masri and Jihad's Fahdi Bati.

The Palestinians sources said Nablus has been termed a leading base for Palestinian insurgents in the West Bank. Fatah, Hamas and Jihad have sent dozens of suicide bombers from Nablus for attacks against civilian targets in Israel.

Over the last week, Israeli paratroopers have been searching the so-called Casbah quarter of Nablus for weapons and insurgents. On Saturday, Israeli soldiers, conducting a house-to-house search, clashed with two suspected insurgents, killing one of them, identified as Fatah operative Nadel Alawi.

Israeli sources said the second insurgent fled into a tunnel located under a house. They said Israeli soldiers, detecting additional people in the tunnel, called on them to surrender and then hurled grenades and fired weapons into the underground lair. Seven people were said to have been killed.

Hours after the shootout, the Fatah-dominated Al Aqsa Martyrs Brigade issued a statement that threatened to avenge the Israeli killings.