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A suicide bomber walked into a crowded hotel dining room in this Israeli coastal resort town Wednesday night and blew himself up as guests sat down to celebrate the start of the Jewish Passover holiday.

Police said at least 19 people were killed, and more than 120 wounded in one of the worst terror attacks in 18 months of escalated hostilities between Israelis and Palestinians.

The Islamic military group Hamas claimed responsibility for the attack in a phone call to the Arab TV station Al-Jazeera, identifying the bomber as Abdel Baset Odeh, from the West Bank town of Tulkarem. The 25-year-old Palestinian had worked in Netanya hotels in the past.

The explosion at the Park Hotel was large enough to cause major structural damage, hampering the efforts of emergency crews.

The blast came as guests prepared to participate in a Passover Seder — the ritual meal that ushers in the eight-day holiday that commemorates the Jews' deliverance from slavery in Egypt. Many hotels cater Seders in their dining halls.

A local police chief, Aharon Franko, said the bomber entered the hotel, crossed the crowded lobby and reached the dining hall, where he blew himself up.

The explosion tore through the ground floor of the hotel, blowing out walls and overturning tables and chairs. Bits of rubble and wires dangled from the ceiling.

In the chaos, one table remained standing, covered by a white cloth and with the elaborate Seder place settings still in place.

"Suddenly it was hell," said one of the guests, Nechama Donenhirsch, 52. "There was the smell of smoke and dust in my mouth and a ringing in my ears."

Donenhirsch said that as she and her family fled, they saw a little girl, about 10 to 12 years old, lying dead on the ground, her eyes wide open as if in surprise.

Some of the wounded were seen staggering out of the lobby of the hotel, which was plunged into darkness by the explosion. One man was covered by a blue blanket and had blood dripping from his face, said witness Joel Leyden.

Leyden said he saw five bodies lined up on the sidewalk outside the hotel, including a woman dressed in her holiday best.

Israel quickly placed the blame on Palestinian leader Yasser Arafat prior to Hamas' claim of responsibility.

"Arafat is to blame for the violence that emanates from the territories under his control," said David Baker, a government spokesman.

"It is clear the Palestinians are bent on using everything at their disposal for killing and maiming as many Israelis as possible anywhere, anytime."

It was not immediately clear how the latest terror attack would affect U.S.-sponsored efforts to negotiate a truce between the Israelis and Palestinians.

The bombing came just hours after Saudi Crown Prince Abdullah presented a new peace initiative at the Arab summit in Beirut, offering Israel normal relations with the Arab world in exchange for a complete withdrawal from the territories it occupied in the 1967 Mideast war.

Arafat, who remains confined to the West Bank by Israel, embraced the initiative in a televised speech, and said he hoped it would be adopted by the summit.

Israeli officials responded guardedly, saying the Saudi plan was too vague and somewhat weakened the idea of "normalization" initially floated by Abdullah. The prince's last-minute addition — a demand that Israel recognize the right of return of Palestinian refugees — is "totally unacceptable," said Danny Ayalon, a Sharon adviser.

U.S. envoy Anthony Zinni has been working on a truce for the past two weeks, but the talks have been punctuated with violence.

Israel has said repeatedly it could not tolerate more attacks on its civilians. Earlier this week, Prime Minister Ariel Sharon convened his security Cabinet to discuss possible options in the event the truce mission fails. One idea raised was a large-scale military operation in the West Bank and Gaza Strip.

President Bush decried Wednesday's bombing and called upon Arafat to end the "cold-blooded killing" in the Mideast.

Secretary of State Colin Powell urged Arafat to go on television and demand an end to attacks against Israelis. The attacks endanger any negotiations toward a Palestinian state, Powell said.

"This sort of activity and the tolerance of this sort of activity will destroy the very vision the Palestinian Authority stands for and Chairman Arafat says he's committed to," Powell said in Washington.

"Today, there was another suicide bomber who murdered innocent Israelis. This callous, this cold-blooded killing, it must stop," Bush said in a speech in Atlanta. "I condemn it in the most strongest of terms.

"I call upon Mr. Arafat and the Palestinian Authority to do everything in their power to stop the terrorist killing, because there are people in the Middle East who would rather kill than have peace."

Israeli police had been on high alert for possible attacks during the Passover holiday, with more than 10,000 officers deployed in potential trouble spots.

The nation's police commissioner, Shlomo Aharonishki, said it was impossible to prevent all attacks. "Even with more policemen and a broader deployment, we cannot block the centers of the cities," he said. "This attack is more evidence of that."

Israel has held Arafat responsible for the string of recent attacks, saying he has done nothing to rein in militants.

Raanan Gissin, a Sharon adviser, said the attack "will require us to reevaluate our overall policy."

"We are still working to achieve a cease-fire to which we are fully committed, but if the Palestinians have decided to choose the road of terrorism ... then we have to decide what measures we will take," Gissin said.

The Park Hotel is located along this coastal town's boardwalk facing the Mediterranean.

Netanya has been a frequent target of Palestinian attackers in the past 18 months of violence between Israel and the Palestinians.

The city's mayor, Miram Feyerberg, said it was impossible to prevent such attacks. "This is a city that can be infiltrated from many different directions. It's simply unbelievable," she said.

On March 9, two Palestinian gunmen tossed grenades and opened fire at a seafront hotel in Netanya, killing a 9-month-old Israeli girl and wounding more than 30 other people. Police killed the attackers. The Al Aqsa Brigades, a group linked with Arafat's Fatah movement, claimed responsibility for the attack.

Fox News' Todd Connor and the Associated Press contributed to this report.