Jerusalem ? A bomb hidden in a bag ripped through a busy cafeteria Wednesday at Hebrew University, killing seven people, including three Americans, in an attack that shattered the peace in one of the few places where young Jews and Arabs still mixed freely.

More than 80 people were also wounded in the second bombing to hit Jerusalem in two days.

Members of the Israeli Border Police round up Arab citizens near the scene of an explosion at Hebrew University in Jerusalem. At least three Americans were killed Wednesday when a bomb was detonated in a crowded cafeteria at the university's Frank Sinatra International Student Center.

Media reports said two of the dead were Israelis and the others were foreign nationals. The injured included Jews and Arabs, but no overall breakdown was available.

Three Americans were killed in the blast and four were injured, State Department spokeswoman Lynn Cassel said in Washington. Their names were withheld pending notification of their families.

But one was identified by a family spokesman as 36-year-old Janis Ruth Coulter, an assistant director of graduate studies based at Hebrew University’s New York office.

Coulter had been escorting American students to Israel when the attack occurred, Harry King said.

“Janis Ruth was a wonderful, loving, caring person,” King said from Boston, where Coulter’s family lives. “Her faith, to which she converted, was at the core of her being.”

Hamas claimed responsibility for the bombing and said it was revenge for Israel’s air raid last week on Gaza City that killed the organization’s military chief, Salah Shehadeh, and 14 civilians, including nine children.

Israel has tried to end Palestinian attacks by sending troops to impose a curfew in most West Bank cities and towns for the past six weeks. After a lull, there’s been an outbreak of shootings and bombings in the past week.

Israel retaliates

Israel’s Security Cabinet, meeting after Wednesday’s blast, decided Israel would retaliate within hours, Israel Radio said. The report could not be independently confirmed.

But early today in the town of Beit Jalla, next to Bethlehem, the Israeli military destroyed the family house of Haza Yusuf, who carried out a suicide bombing attack Tuesday in Jerusalem that wounded seven Israelis, the military said in a statement. Military sources said the destruction was a deterrent measure to show that such actions have a price.

President Bush condemned the bombing “in the strongest possible terms,” and said it was perpetrated by “killers who hate the thought of peace.”

U.N. Secretary-General Kofi Annan also condemned the attack and again urged Israelis and Palestinians “to end the cycle of violence, revenge and retaliation.”

‘Island of tolerance’

The lunchtime blast in the university’s Frank Sinatra International Student Center struck a popular student hangout at a school that’s been an island of tolerance throughout the nearly two years of Mideast fighting.

Alastair Goldrein, 19, from Liverpool, England, said the cafeteria was a gathering place for students of all backgrounds.

“I was on my way to lunch. There was a huge, huge explosion. Everything shook, and then there was this deathly silence,” said Goldrein, who has been taking courses in Jewish studies for the past year. “I ran in, there were people lying around wailing, covered in blood. Scenes that are indescribable, clothes and flesh torn apart.”

The bag with the bomb was placed on a table in the center of the cafeteria, police said. “It was not a suicide bomber,” said police spokeswoman Sigal Toledo. The blast brought down part of the ceiling and blew out windows.

The attack marked a departure from the suicide bombings that have rocked Israel throughout 22 months of Mideast fighting. It was not clear, however, whether it marked a change in tactics, or a one-time attack aimed at exploiting a weakness in the university’s security.

U.S. ties

Spencer Dew, 26, an American student from Owensboro, Ky., who was lightly wounded by flying glass, said he had worried about such attacks in Israel, “but it didn’t deter me from coming. I assume I’ll come back next year.”

The explosion occurred at the university’s Mount Scopus campus, a Jewish enclave surrounded by Palestinian neighborhoods in the eastern part of the city. The student center was named for Sinatra, who attended the 1978 dedication of the building.

Money for the student center was raised by members of the Friends of Hebrew University from the west coast of the United States, many of whom had connections in the entertainment industry.

Police maintain heavy security at the university, with student backpacks checked thoroughly by guards at entrances, students said.

However, Benny Vered, deputy editor of the school newspaper, said the perimeter fence was easy to cross. In April, the newspaper paper predicted such an attack, he told Israel Radio.

“I held a sign that said ‘terrorist’ and crossed back and forth over the fence for 40 minutes,” he said, adding that no one stopped him or even appeared to notice.

The university said 23,000 students attend the school, about 5,000 of them Arabs and 1,500 from abroad.

Hamas, which has carried out the largest number of Palestinian bombings, claimed responsibility for the bombing during a rally in Gaza City that drew some 10,000 supporters into the streets following evening prayers in the mosques.

“This operation today is a part of a series of operations we will launch from everywhere in Palestine,” said a masked Hamas militant, dressed in a green military uniform.

At the request of the masked Hamas speaker, the entire crowd knelt to pray that future Hamas attacks “would succeed against the enemy of God.”

Shortly before Wednesday’s attack, the Rev. Jesse Jackson met Yasser Arafat at the Palestinian leader’s West Bank headquarters in Ramallah. Palestinian authorities were “continuing our efforts, and will continue, from every aspect, to stop the violence,” Arafat said at a joint news conference.

Jackson was to go to Gaza to meet Hamas’ spiritual leader Sheikh Ahmed Yassin. But he said he canceled the meeting to show respect for the victims. “This was not an act of liberation. This was an act of terror against innocent people,” he told The Associated Press.

In Washington, State Department spokesman Philip Reeker welcomed Jackson’s decision to cancel his Gaza meeting. “We don’t think that meeting with Sheik Yassin or other leaders of foreign terrorist organizations is a good idea,” he said.

Revenge predicted

Even before Hamas claimed responsibility, Yassin had linked the bombing to last week’s Gaza airstrike and said Israel should have expected a revenge attack.

“When Israel bombs a civilian building full of women and children, and kills 15 people this is the response they should expect,” he said.

The Palestinian Authority said in a statement that it “absolutely condemns the attack against Hebrew University.” However, the Palestinian leadership also said it “considers Israeli Prime Minister Ariel Sharon responsible for this cycle of terror.”

Sharon’s government has slightly eased the tough restrictions placed on Palestinian movements, but the latest attacks could lead to even tougher measures.

“Israel is fighting a pitched battle against terror, and for the right to walk down the street, take a bus or sit in a cafeteria without the fear of being decimated by Palestinian terrorism,” said David Baker of the prime minister’s office.

On Tuesday, a Palestinian suicide bomber blew himself up at a fast-food stand in Jerusalem, wounding several Israelis.

After withholding tax revenues from the Palestinians for much of the past 22 months, Israel on Wednesday transferred $15 million to the cash-strapped Palestinian Authority.

Israel had withheld an estimated $600 million in tax money since shortly after the fighting erupted in September 2000. Aid groups say the number of undernourished Palestinian children has risen sharply. Palestinian unemployment is rampant.