(AP) – JERUSALEM – A Palestinian attacker shot dead a security guard then blew himself up inside a packed beach restaurant Saturday, killing at least 18 people and wounding dozens, according to Israeli police. It was one of the bloodiest attacks in the past three years of fighting. The deadliness of the attack — on the Sabbath before the Jewish holiday of Yom Kippur — raised the possibility that Israel could take action against Palestinian leader Yasser Arafat. Following the last suicide attack, nearly a month ago, the Israeli Cabinet threatened to expel Arafat.

About two dozen people were wounded in the attack on the Maxim restaurant in the northern Israeli port city of Haifa on Saturday.

Police said a suicide bomber shot dead the security guard before entering the restaurant — a first in more than 100 suicide bombings in the past three years. In some past attacks, guards have succeeded in stopping suicide bombers or in preventing them from reaching crowded areas, limiting casualties from the explosions.

The bomber then entered the restaurant and detonated explosives strapped to his body. Police said 18 were killed, including the guard who was shot, and a television report said five of the dead were children.

After the blast, television images showed bullet holes in the restaurant windows. A person dressed in the reflective vest commonly worn by security guards outside of restaurants and public places was seen lying face down on the front steps.

The attack came despite a blanket closure Israel had imposed Friday on the West Bank and Gaza Strip ahead of Yom Kippur, or Day of Atonement, which begins at sundown Sunday and ends at sundown Monday. Such closures are generally imposed during Jewish holidays because of increased concerns about attacks by Palestinian militants in such periods.

There was no immediate claim of responsibility for Saturday’s attack, the first suicide bombing since twin attacks killed 15 people on September 9, near an army base outside Tel Aviv and at a Jerusalem coffee shop. Since fighting broke out three years ago, more than 400 Israelis have been killed in 103 Palestinian suicide bombings.

After those bombings, Israel threatened to “remove” Arafat, but did not say when it would take action. Soon after the decision, Israeli Prime Minister Ariel Sharon implied action would be taken against Arafat if there was another major suicide bombing with heavy casualties.

Palestinian chief negotiator Saeb Erekat condemned Saturday’s attack and appealed to the quartet of international mediators — the United States, the European Union, Russia and the United Nations — “to exert every possible effort in order to ensure de-escalation, and to maintain the road map” peace plan.

David Baker, an official in Israeli Prime Minister Ariel Sharon’s office, said Israel demands that the Palestinian Authority take immediate steps against militant groups.

“The bombing in Haifa is another indication that the Palestinian Authority continues to refuse to take even minimal steps against the terrorist infrastructure,” he said.

The attack came after the violent Hamas group declared that a series of fences, razor wire and trenches Israel is building around the West Bank would not stop suicide bombers from reaching Israeli cities. The militant group also said it would continue to send Palestinians to blow themselves up inside Israel.

“This wall will not protect the Zionist entity and will not stop the attacks of resistance and, God willing, the day will come when this wall will collapse as the Berlin wall collapsed,” said a statement, signed by Hamas, posted on a pro-Hamas Web site late Friday night.

Hamas has been behind most of the suicide bombings against Israeli targets during three years of fighting.

Earlier this week, the Israeli Cabinet approved a new phase of the barrier project that will add fences deep inside the West Bank to shield four large Jewish settlements. Palestinians and the United States have opposed the path of the barrier, saying it would pre-empt peace agreements and unilaterally define the border of a Palestinian state.

Israeli officials have said wide gaps would be left — for now — between the new fences and the main barrier being built closer to Israel’s frontier with the West Bank. Connecting the fences would slice the West Bank in half.

About one-fourth of the barrier project has already been built in the northern West Bank. In places, it runs close to Israel; elsewhere it dips farther into the West Bank, isolating several Palestinian villages and cutting some residents off from their land.

Israel says the barrier is essential to try to stop Palestinian suicide bombers and other attackers from reaching Israel, where they’ve killed hundreds during fighting that’s lasted three years. Israeli officials point to the success of a fence that’s been in place for years along Israel’s edge with the Gaza Strip. No suicide bombers have succeeded to cross it.

In an interview published Saturday in the Washington Post, Secretary of State Colin Powell said Israel’s effort to dampen criticism by leaving gaps in the new phase of the fence was not satisfactory.

Powell indicated that the route should stick to the “green line,” the frontier between Israel and the West Bank before the 1967 Mideast War.

“The more you intrude in Palestinian areas and the more it looks like it could be contiguous intrusion around large sections of Palestinian land that would prejudge subsequent negotiations as to what a Palestinian state may look like, that’s a problem,” Powell said.