GAZA CITY, Gaza Strip — Palestinian leaders condemned the predawn assassination of the former head of general security in Gaza yesterday, pledging to capture his killers to demonstrate that the elected government is in control of this coastal strip.

Moussa Arafat, a cousin of the late Palestinian leader Yasser Arafat, was dragged from his three-story home here by more than a dozen gunmen shortly before 5 a.m. and shot in the street. His son, Manhal, a major in the Palestinian military intelligence service, was kidnapped. Three bodyguards were also taken from the house but were soon released unharmed.

Hours later, the Popular Resistance Committees, a faction comprising disaffected members of various Palestinian parties, asserted responsibility for the assassination.

Moussa Arafat, a founding member of the ruling Fatah movement, had a reputation for corruption that made him unpopular among many Palestinian factions, including his own. He held the rank of minister and served as Palestinian leader Mahmoud Abbas' military-affairs adviser, a symbolic position he held after being fired as head of Gaza's general security agency in April.

The attack was seen as a serious challenge to Abbas as he embarks on an ambitious economic-recovery plan to follow the imminent Israeli withdrawal from the one-fifth of the Gaza Strip used for decades for Jewish settlements.

The Web site of the Haaretz newspaper reported that Abbas had canceled his visit next week to the United Nations because of the deteriorating security situation and the Israeli pullout.

Information Minister Nabil Shaath suggested that the assassination was timed to raise doubts about the Palestinian Authority's ability to maintain order in Gaza. The Israeli government withdrew troops and residents from all 21 Jewish settlements in Gaza and is scheduled to begin handing over assets to the Palestinian Authority next week.

Members of the Popular Resistance Committees were arrested by the Palestinian police on suspicion of involvement in an attack on a U.S. diplomatic convoy in the Gaza Strip in 2003 that killed three Americans. However, some of the suspects were later released on the grounds that there was insufficient evidence against them, and others were freed from Gaza's central jail by fellow militants.

Abbas largely succeeded in persuading Islamic militants to halt their attacks on Israeli forces during last month's contentious process of forcibly removing thousands of recalcitrant settlers who refused to leave their homes. But, in recent weeks, gangs affiliated with local clans have briefly kidnapped international aid workers and a French journalist in an effort to put pressure on the Palestinian government to release family members.

Police officers upset about low pay have gone on strike and burned tires to block the coastal road. Meanwhile, Israel said yesterday it was closing the Rafah crossing between Gaza and Egypt temporarily, in the apparent absence of a deal with the Palestinians for freer movement in and out of Gaza.

A Palestinian Authority official condemned the closing of Gaza's main link to Egypt.

Compiled from The Washington Post, Knight Ridder Newspapers, Chicago Tribune and Reuters reports