Israeli troops exchanged fire with Palestinian militiamen for four hours early Tuesday, killing three gunmen before withdrawing from the outskirts of a refugee camp, witnesses said.

The army confirmed the firefight near the Maghazi refugee camp in the central Gaza Strip, and said several Palestinians were hit by army fire. It said troops were conducting searches, but did not say what the target of the operation was.

The firefight erupted about midnight and lasted until 4 a.m. Tuesday, witnesses said. Dozens of gunmen from several militias fought with troops backed by tanks and two helicopter gunships, the witnesses said.

Among the three gunmen killed were two members of the Al Aqsa Martyrs' Brigade, a militia linked to Yasser Arafat's Fatah movement, and an activist in the militant Islamic Jihad group, according to followers of the two groups.

Near Khan Younis in the southern Gaza Strip, an exchange of fire broke out as the army cut down trees it said were used by gunmen as cover for shooting at a nearby military outpost, the army said. Palestinian witnesses said the army demolished two empty buildings in the operation.

Near the West Bank city of Nablus, the army blew up the homes of two senior militants, one from the Al Aqsa militia and the other from a radical PLO faction, the Popular Front for the Liberation of Palestine.

The Al Aqsa member, Habash Abu Saoud, died in a July shooting attack on a nearby Jewish settlement in which five Israelis were killed. The second home belonged to Kamil Abu Khomeish, the fugitive leader of the PFLP militia in the Nablus area, who allegedly planned several attacks on Jewish settlements.

Each house had three floors, and 20 people were made homeless by the demolitions, residents said. The army confirmed the demolitions.

Israel's Cabinet decided Monday to intensify operations against suspected militants and their hideouts after a double suicide bombing in Tel Aviv on Sunday killed 22 bystanders and injured more than 100.