A Palestinian man detonated explosives strapped to his body outside a popular mall here Tuesday, killing himself and three Israeli women in the first suicide bombing in Israel in nearly five months.

Israel announced a complete closure of the West Bank and military officials said they would respond harshly in the coming days against Islamic Jihad, a militant group that asserted responsibility for the attack. Palestinian leaders condemned the bombing as a terrorist attack, but Israeli officials said it was evidence of the Palestinian Authority's unwillingness to fight the various armed groups opposed to Israel.

Israeli officials said they did not think the blast would disrupt Prime Minister Ariel Sharon's plan for a withdrawal from Jewish settlements in the Gaza Strip and West Bank scheduled for next month.

The bomber was identified as Ahmed Abu Khalil, 18, a student from the West Bank village of Atil about 15 miles east of here. Police officials said Khalil detonated 22 pounds of explosives at about 6:30 p.m. as he crossed the intersection outside the glass-and-granite entrance to the HaSharon Mall, a target of suicide bombers twice before during the intifada, or uprising, that began in September 2000.

Witnesses described badly burned bodies scattered in Herzl Street, a busy commercial strip here. An assortment of scorched sandals and sneakers covered the crosswalk, some resting in pools of blood.

"Suddenly there was an explosion, and it came like a ball of fire," said Betty Levi, 16, who was among more than four dozen people brought to Laniado Hospital here following the attack. Much of Levi's body was burned and her legs were badly injured after being showered with ball bearings and other bits of metal packed into the bomb. "There was a women next to me who was burned," she said from her hospital bed. "I got up and ran toward the mall."

The attack was the first suicide bombing in Israel since Feb. 25, when a member of Islamic Jihad blew himself up outside the Stage Club in Tel Aviv, killing five people. Tuesday's attack came about an hour after another attack east of Netanya in the Jewish settlement of Shavey Shomron in the West Bank.

A stolen car broke through the settlement gates and detonated, injuring the driver but causing no other casualties. Israeli military officials said the driver, a member of Islamic Jihad who had been working as an informer for Israel, was handcuffed to the steering wheel. The bomb he was carrying was detonated by cell phone.

The officials suggested that the man's collaboration with Israel had been discovered and that he was marked for retribution. He belonged to the same cell of Islamic Jihad, they said, that sent the bomber to Netanya Tuesday.

This seaside resort city on the narrowest stretch of Israel's coastal plain has been struck by six suicide bombings since the start of the intifada, most recently in March 2003 when a bomber wounded 40 people in an outdoor cafe. Hamas and the Popular Front for the Liberation of Palestine, which have both largely adhered to the current cease-fire, asserted responsibility for that attack.

The HaSharon Mall has been struck three times by suicide bombers, including an attack in 2001 that killed five people. The mall sits at the entrance to the city along a highway that leads to Tulkarm, a West Bank city less than 10 miles east of here. Israeli forces occupied Tulkarm in the spring of 2002 after members of Hamas bombed the Park Hotel in Netanya, an attack that killed 29 people and marked a turning point in the intifada. Since then, Israel has completed construction of a 24-foot-high wall that officials say has reduced suicide bomb attacks. The officials said they did not know how the bomber reached Netanya on Tuesday.

As part of a February cease-fire announced by Sharon and Palestinian leader Mahmoud Abbas, Israel returned Tulkarm to the control of Palestinian security services four months ago while maintaining a presence in rural areas such as Atil. Israeli officials have complained since then that Abbas, who has met with leaders of Hamas and Islamic Jihad in Damascus in the past week, has done nothing to confront radical Palestinian groups that have carried out suicide bombings.

"Instead of fighting them in Israel, he is embracing them in Damascus," said Gideon Meir, a senior Israeli Foreign Ministry official.

Meir said he did not believe the attack would derail Sharon's plan to evacuate 21 Gaza settlements and four others in the northern West Bank, a process known as disengagement. He said when Sharon says "there will not be disengagement under fire, he means we will not stop disengagement. We will stop the fire."

While Hamas has been moving into mainstream Palestinian politics, the smaller Islamic Jihad has remained outside of the process begun by the 1993 Oslo accords. With roots in the Muslim Brotherhood, Islamic Jihad refuses to recognize Israel and receives much of its financing and direction from Iran, according to Israeli officials.

Israeli and Palestinian officials say the group is seeking to disrupt the Gaza evacuation.

Islamic Jihad gunmen have attacked West Bank settlers and Gaza soldiers in recent weeks. Israeli forces have arrested more than 300 of the group's members and killed one of its leaders near the city of Jenin. The Reuters news agency reported that Khalil, the bomber, said in a videotaped farewell that he was carrying out the attack because of Israeli violations of the cease-fire.

Speaking to reporters, Abbas called the bombing "a terrorist attack because it is a crime against the Palestinian people." He added: "They are operating against the interests of the Palestinians. No one with any sense in his mind could be behind an act like this just before the Israeli withdrawal."

Special correspondents Samuel Sockol and Hillary Claussen contributed to this report.

Police investigators inspect the site of a suicide bombing at a junction outside a mall in the Israeli town of Netanya. The radical Islamic Jihad asserted responsibility for the attack, and Israeli officials said they would respond harshly against the group.