A bomb exploded in a West Bank high school on Wednesday, injuring at least 20 students, three of them seriously, police said. A student at the school in Jaba, a village outside Jenin, was playing with a bomb before it exploded, police said. It was unclear how large the bomb was or whether the student brought it or found it. The Israeli occupation army said none of its forces were in the area.

Israeli Air Strike Kills Hamas Commander

A missile fired by an Israeli aircraft blew up a car in Gaza City, killing a top Hamas commander and six other people in an attack that ended a lull in Israeli airstrikes since the beginning of the war in Iraq .

The killing of Saed Arabeed, 38, on Tuesday was followed by a string of attacks. Hamas resistance men retaliated by shooting a rocket at the Israeli town of Sderot on Wednesday, and Israeli occupation troops said they opened fire on another group of Palestinians approaching a rocket launcher. Doctors said two farmers were wounded by gunfire.

In a separate clash, troops shot and killed a 21-year-old man who was standing near a group of children throwing rocks at soldiers, Palestinian doctors said. Occupation army officials did not immediately comment.

On Tuesday, two Israeli F-16 warplanes flew low over Gaza City after nightfall, breaking the sound barrier minutes before a missile slammed into a white Subaru on a street in Gaza City, turning the vehicle into a pile of flaming rubble. A second missile exploded in the street, wounding at least 50 bystanders, witnesses and doctors said.

Israeli security sources said the airstrike had targeted Arabeed, a senior Hamas commander responsible for a series of deadly raids against Israelis over the past decade. Two of the other dead were Hamas activists, Palestinians said.

The other dead and wounded were civilians, including children, doctors said. They were hit by shrapnel from the second missile, which exploded after people had run into the street to see what had happened.

Hamas officials threatened revenge and tied the airstrike to the war in Iraq, though Israel had toned down its military operations during the fighting in the Gulf, an apparent effort to keep a low profile amid Arab charges that Israel was the main beneficiary from the Iraq war.

The strike put an end to a period of apparent restraint, returning to a pattern in which Israel strikes at Hamas leaders whenever it can. The violent Islamic group has been responsible for attacks that have killed hundreds of Israelis in 30 months of fighting, and Israeli leaders have pledged to destroy its infrastructure and cripple its leadership.

Marwan Abdel Hakim, a Hamas member, likened the Israeli attack to the Iraq war.

"Our blood had been shed by the same enemy, by the same kind of weapons and for the same goal," he said, "to kill any hope for Arab and Muslims to establish a united Arab country and to defeat the enemy of God."

Israel has carried out many similar attacks against suspected Palestinian activists during 30 months of Palestinian-Israeli violence. Palestinians and human rights groups have condemned the practice.

The Israeli security sources, speaking on condition of anonymity, said Arabeed directed Hamas attacks alongside Mohammed Deif, long at the top of Israel's wanted list and himself wounded in a previous Israeli air strike.

Among the attacks attributed to Arabeed was a resistance bombing on a Tel Aviv bus in 1994 in which 21 people were killed.

In political developments, the Palestinian prime minister-designate was running into obstacles from Yasser Arafat in trying to put together a new Cabinet. The disputes could delay publication of a U.S.-backed Mideast peace plan, and President Bush was showing some impatience.

It appeared that Mahmoud Abbas, the Palestinian prime minister-designate, would not present his Cabinet on schedule Thursday. Palestinian law allows him to ask for an extra two weeks.

Publication of the peace plan depends on Abbas assuming power. The plan, sponsored by the United States, Europe, Russia and the United Nations , is known commonly as the "road map" and calls for Palestinian statehood in 2005 at the end of a three-phase process.

The plan was delayed first by Israel's elections in January and then by the process of appointing the Palestinian prime minister. Speaking in Belfast, Northern Ireland on Tuesday after meeting British Prime Minister Tony Blair , Bush hinted at impatience.

"I look forward to him (Abbas) finally putting his Cabinet in place so we can release the road map," he said.

Arafat grudgingly appointed Abbas, his longtime PLO deputy, as premier, giving in to intense international and domestic pressure to reform his corruption-plagued regime.

Israel and the United States had declared a boycott of Arafat, charging that he was implicated in terrorism. Both hoped that the appointment of Abbas would signal that Arafat was turning over significant power, allowing Abbas to run daily affairs and security and have a hand in peace negotiations.

But Palestinian officials and Western diplomats, speaking on condition of anonymity, said that instead, Arafat is raising obstacles and trying to cling to as much power as possible.

Using his Fatah movement as a base, Arafat is trying to override Abbas' intention to replace most of the Cabinet, turning out veteran politicians and Arafat aides.

PHOTO ACPTION

Palestinian firefighters work as others inspect the wreckage of a burned car after an Israeli F-16 warplane fired a missile at it in Gaza city, Tuesday April, 8, 2003. Palestinian medical official said five people were killed and 47 wounded, eight critically during an Israeli air strike on the car in Zeitoun neighborhood of Gaza City. (AP Photo/Adel Hana)