An Israeli helicopter fired missiles at a car in a densely populated neighborhood of the Gaza Strip (search) on Saturday, killing three Islamic militants and wounding 15 people, doctors said.

Three of the wounded were in critical condition after the airstrike between Gaza City and the Jebaliya refugee camp. The wounded included three children, one of whom was among those in critical condition, the doctors said.

The two missiles hit with a thunderous explosion. Palestinian security officials strained to keep order around the scene as surging crowds jumped on the wreckage and called for revenge.

Israel said the car carried senior Islamic Jihad (search) militants who planned several attacks on Israelis. The military said it believed the men were transporting explosives in the car.

There has been speculation Israel will step up its strikes against militants before a possible withdrawal from much of the Gaza Strip in an effort to prevent militants from claiming that they drove out Israeli forces.

Two advisers to Prime Minister Ariel Sharon (search) were leaving for Washington late Saturday to discuss his unilateral withdrawal plan with National Security Adviser Condoleezza Rice (search). Sharon has said he would coordinate any pullback with the United States.

Islamic Jihad identified the three men killed in Saturday's strike as Mahmoud Judah, a field commander of the group's military wing; militant Ayman Dahdouh; and Dahdouh's cousin, Amin, a group supporter but not a militant. Two of the bodies were decapitated in the attack.

In a statement, Israel's military said the strike's main target, Judah, directed many attacks on Israelis, including one in October when two gunmen killed three Israeli soldiers as they slept in their barracks in the Jewish settlement of Netzarim (search).

Israel frequently has sent helicopter gunships and warplanes to kill Palestinian militants in targeted missile strikes during more than three years of fighting. The last such strike was Feb. 7, when an Islamic Jihad leader and a 12-year-old boy were killed.

An Islamic Jihad spokesman said the group will continue battling Israel.

"God willing, Palestinians will win this battle of honor and will achieve victory and will liberate the Holy Land," Khalid al-Batch said.

In other developments, Palestinian gunmen in black ski masks burst into a Gaza office of the Palestinian Broadcasting Corp. on Saturday and demanded work, a day after the mayor of the West Bank's largest city resigned to protest Yasser Arafat's failure to stop such violence.

The growing chaos comes as the Palestinian leader tries to silence dissatisfaction with his rule and rebellion from younger reform-minded activists in his own Fatah movement.

Fatah leaders met Saturday to plan internal elections. Arafat promised disgruntled activists a vote would be held within a year, and on Saturday a committee was formed to prepare for elections, Cabinet Minister Jamal Shobaki said.

But few of the young activists believed Arafat, who has fought reforms and kept a tight hold on power, would keep his word. He has surrounded himself with cronies and Fatah movement stalwarts he brought with him on his return from exile in 1994.

Also, Israeli bulldozers leveled 120 Palestinian shops close to a crossing point between Gaza and Israel. The military said the shops sat over a tunnel used by two gunmen, who infiltrated the heavily fortified Erez crossing and killed a soldier earlier this week.

Twisted metal and concrete was all that remained in the flattened lot, about the size of a soccer field. Beit Hanoun's mayor said Friday's destruction caused about $1 million in damage.

During the last of four days of Fatah meetings, leaders also discussed the role of the Al Aqsa Martyrs' Brigades, a militant group operating in small and relatively autonomous gangs, some with ties to Fatah. Others are funded by Lebanese Hezbollah guerrillas.

Fatah leaders warned that if Al Aqsa wanted to maintain links to the movement, it should end attacks on Israeli civilians, said Jibril Rajoub, a top Arafat security adviser.

But Fatah also restated its position that attacks on Israeli soldiers and settlers within the West Bank and Gaza would be sanctioned until Israel withdraws from Palestinian areas and an independent Palestinian state is born.

"The struggle in the areas of the occupied territories is legal, and we emphasize this point," Rajoub said.

It appeared unlikely the gunmen would pay any heed anyhow, having ignored recent Fatah efforts.

Al Aqsa gunmen have attacked Israelis many times in more than three years of fighting. The group claimed responsibility for two recent Jerusalem bus bombings that killed 18 Israelis and a foreign worker.

The group also has terrorized residents in Nablus, where the mayor, Ghassan Shakaa, resigned to protest the unchecked mayhem in his city of 180,000.

In a letter published in Palestinian newspapers Saturday, Shakaa, a longtime Arafat ally, wrote that the Palestinian Authority has allowed the city to slip into disorder.