Palestinian police were searching Tuesday for an Israeli Arab producer for CNN who was kidnapped at gunpoint from his van, and the TV network joined journalists' associations in demanding his immediate release.

It was not clear whether the kidnapping signaled a new practice by Palestinian militants — perhaps an attempt to copy Iraqi insurgents who have snatched dozens of foreigners — or whether the producer, Riad Ali (search), was taken for personal reasons.

In the West Bank, troops shot dead a Palestinian in the Jenin refugee camp (search), local hospital staff said. Camp residents said the man, Baleh Bilalu, 46, had a history of mental illness and was wandering in the dark in a section of the camp under military curfew when soldiers shot him.

The army said the man was climbing a fence surrounding an army position and when he refused several calls to halt, troops opened fire.

The motive of Monday evening's kidnapping of the CNN producer was not clear. By midday Tuesday, the kidnappers had still made no public statement or demand, and Palestinian militant factions denied involvement.

In four years of fighting with Israel, militant groups have carried out scores of suicide bombings and shooting attacks, but have refrained from kidnapping non-Palestinians as a way of extracting concessions from Israel.

Ali had been singled out by the kidnappers, and there was speculation someone had a personal grudge against him.

Militants might also have opened a new front by targeting an Israeli journalist following the assassination of a Hamas leader in Syria on Sunday. Israeli security sources have acknowledged involvement in the killing, and Hamas, weakened after a string of killings of its leaders, has vowed revenge.

Palestinian Prime Minister Ahmed Qureia on Tuesday said authorities were working hard for Ali's release and urged the kidnappers to free him.

"It is wrong and criminal. It must be ended," Qureia said. "What will be achieved?"

Witnesses said an old-model Peugeot 504 carrying gunmen stopped a CNN van outside a supermarket late Monday in Gaza City's Rimal neighborhood, close to the Ramattan Studios that provide services to foreign TV companies.

CNN correspondent Ben Wedeman said three armed men walked up to the van, asked for Ali and took him away. Wedeman, a second American and their Palestinian driver were left alone, he said.

CNN said in a statement it had not heard from the abductors. The network, along with the Foreign Press Association (search) and the Palestinian Journalists Association (search), demanded his immediate release.

Israeli Arab journalist Rafik Halabi (search), who supervised Ali when he worked at Israel TV, said Ali has not been harmed.

"What I understand, what I know, is that Riad, my good friend and colleague, is alive and well," Halabi told Army Radio, refusing to elaborate. The radio station said contact had been made with the kidnappers, but gave no further details.

During four years of Israeli-Palestinian fighting, foreign and Israeli Arab journalists have felt relatively safe in Gaza. In one of the few incidents of violence against foreign journalists, Palestinians attempted to kidnap a New York Times correspondent last May, but the reporter escaped.

However, Gaza has grown increasingly chaotic in recent months amid growing discontent with the weakened Palestinian Authority and ahead of a planned Israeli withdrawal from the area next year.

Palestinian gunmen in Gaza have seized several foreign aid workers and local officials in recent months, but released them after a few hours, often under pressure from their leaders. Tensions have escalated since Sunday's car bombing in Damascus that killed a Hamas leader.

After Monday's kidnapping, two police cars were parked outside Ramattan Studios and police stopped several Peugeot cars similar to those used by the kidnappers. Police were searching for Ali, security officials said.

The Israeli military closed the main crossing from Israel into Gaza, used by Palestinians, diplomats and reporters, "following security assessments and security alerts." The military would not say if the decision was tied to the kidnapping.