The former head of general security in Gaza, Moussa Arafat, was killed early Wednesday when gunmen stormed his Gaza City home and shot him, Palestinian officials and witnesses said. The incident threatened to aggravate tensions among Palestinian factions now struggling for power in the Gaza Strip following Israel's evacuation of its 21 Jewish settlements there.

Witnesses said Arafat, 65, a cousin of the late Palestinian leader Yasser Arafat, was killed shortly before 5 a.m. Moussa Arafat's son, Nimhel, who also worked in the security services, was missing. Witnesses said it was unclear if he had been kidnapped or had managed to escape.

Arafat's appointment last year to be head of security in Gaza, one of the three most powerful posts in the strip, sparked the most serious internal strife in years among Palestinians. The decision triggered an uprising in the streets by the al-Aqsa Martyrs Brigade, the armed wing of Yasser Arafat's Fatah movement, whose young leaders had been calling for sweeping changes inside the ruling Palestinian Authority.

Members of al-Aqsa sacked the authority's military intelligence headquarters and burned other offices in the strip. Yasser Arafat was forced two days later to place his cousin under the authority of Brig. Gen. Abdel Razek Majaide, who was named head of security for all of the Palestinian territories.

Moussa Arafat escaped injury in October when a car bomb exploded near his convoy in Gaza City, an attack he called an assassination attempt. He was removed from his job in April by Palestinian leader Mahmoud Abbas, who replaced Yasser Arafat after his death in November.

Shortly after Moussa Arafat's killing Wednesday, Abbas convened an emergency meeting of the Palestinian security chiefs and Prime Minister Ahmed Qureia.

The slaying added to tensions that had already been high in the days ahead of Israel's scheduled transfer of land, water wells and other assets in Gaza to the Palestinian Authority.

On Tuesday, Israeli soldiers clashed with a group of stone-throwing Palestinians attempting to enter an evacuated settlement in the Gaza Strip, killing a Palestinian man and wounding three others, according to Palestinian witnesses and Israeli military officials.

It was the first fatal encounter between Israeli soldiers and Palestinian demonstrators in Gaza since Israel's pullout last month.

Witnesses gave conflicting accounts of what occurred outside Neve Dekalim, the largest Gaza settlement, just before 7 p.m. With the settlement now mostly razed, its land and remaining public buildings are considered valuable assets in the poor, crowded coastal strip.

The Israeli military said scores of Palestinians from the adjacent Palestinian city of Khan Younis began gathering outside the settlement about 4 p.m., as has been the daily routine for the past week. Many carried the banners of various Palestinian factions, including the Islamic Resistance Movement, or Hamas, according to Israeli military officials.

Palestinian security forces have been keeping the narrow strip between Khan Younis and the settlement bloc clear of Palestinian demonstrators in recent days, but Israeli military officials said they did not do so Tuesday after being alerted to the growing crowd by Israel's Southern Command.

Some witnesses said 200 Palestinians then stormed the fenced settlement grounds; others said the group was smaller. Israeli officials said about 60 Palestinians began tearing down the fence and pouring inside the community, where a small number of Jewish settlers are continuing to gather possessions and workers are demolishing houses. Military officials said soldiers began firing from two posts, aiming low at Palestinians running into the settlement. Palestinian witnesses said the firing appeared more indiscriminate.

"Until the last soldier or civilian leaves, we will not allow any Palestinians to get inside" the Gaza settlements, an officer with Israel's Southern Command said in a telephone interview.

Some of those who managed to get through the fences climbed onto an Israeli tank at the edge of the settlement.

Hospital officials in Khan Younis identified the Palestinian killed as Nimar Saaduni, 18.

Meanwhile, Israeli officials said construction of 117 additional housing units had been approved for Ariel, a Jewish settlement in the West Bank where 18,000 Israelis live. Prime Minister Ariel Sharon has said the settlement, which sits roughly 12 miles inside the West Bank, would remain a part of Israel in any final peace agreement with the Palestinians.

An Israeli official with Sharon's office said the construction would comprise three apartment buildings on a lot inside the settlement's boundaries. Although the Bush administration has called for a freeze on all settlement activity, Israeli officials argue that building inside existing boundaries is allowed. Palestinian officials condemned the new construction.

Moussa Arafat, cousin of Yasser Arafat, was appointed the head of general security in Gaza last year, prompting serious strife among Palestinian factions.