A powerful bomb exploded today in an ultra-Orthodox neighborhood of Jerusalem at the end of the Jewish Sabbath, killing at least nine people. VIDEO

Israeli medics work at the scene of a suicide bombing in an Orthodox Jewish neighborhood.

The police said they believed that the attack was the work of a suicide bomber but they did not rule out the possibility of a car bomb.

The explosion gutted a white four- door sedan, blasting its hood up, charring its sides and blowing out its tires. The bodies of the dead were collected in black bags by the side of the street.

Fifty-seven people were wounded, the police said. Two uninjured babies were taken to one hospital, the whereabouts of their parents unknown.

The explosion took place outside a yeshiva with a guesthouse for students and families visiting during the Sabbath.

Minutes after the blast, as medics rushed the wounded to ambulances, hundreds of men in black hats and long black coats milled in the narrow streets of the Beit Yisrael neighborhood, the flashing lights of emergency vehicles pulsing red against the stone houses.

One man, with blood smeared on his left cheek and throat, spoke urgently into a cellular phone. "Everything's fine, everything's fine," he said in Hebrew.

An elderly man, his white T-shirt stained with blood, leaned heavily against a woman who helped him from the scene.

If a suicide bomber was responsible, it was the first such bombing in Jerusalem in more than a month, and the most deadly such attack in Israel since Dec. 2, when a bomber on a bus in Haifa killed himself and 15 others. Another suicide bomber blew herself just outside Jerusalem on Wednesday night, injuring three border policemen.

Israeli officials called the bombing a Palestinian attack and held Yasir Arafat, the Palestinian leader, responsible.

Mickey Levy, the Jerusalem police chief, said that a bomber had apparently walked up to a group of people and set off an explosive packed with shrapnel. Mr. Levy suffered a heart attack after the last suicide attack here, on Jan. 27. He underwent surgery and has since recovered.

"I was just parking my car, and getting ready to get out of it, then the car in front of us blew up and caught flame," a man who gave his name as Zion told Israel television.

"There were lots of people on the street," he said. "We were here for a bar mitzvah party, and I could see at least three dead people. I ran to look for my family."

Another witness, who did not give her name, said she was walking down the street just before the blast.

"I could see a woman walk into the building with her baby, and a second later the car went up in flames," she said. "I don't know if she's all right. Part of the building caught fire, and shattered glass fell everywhere. It was an awful sight."

More than a year ago, a bomb went off in the same neighborhood, injuring no one. But residents here said they felt safe.

"This neighborhood has been spared, mostly," said Barry Breskin 21, of Rockland County, N.Y.

Mr. Breskin, who is studying at a yeshiva here, said that the blast took place outside a building where seminars on Jewish thought are held each Friday and Saturday. "Generally, now, they're all filtering out to go home," he said.

The Sabbath, or Shabbas, lasts from sundown Friday to sundown Saturday, and during that time observant Jews do not drive or use electrical appliances.

"We can't even call our parents now and tell them we're O.K.," Mr. Breskin said. "In America, it is still Shabbas."

Tonight's blast came while Israeli forces were still operating in two Palestinian refugee camps in the West Bank. The raids marked the first time Israeli forces had entered such camps, which Israel regards as breeding grounds for terorrism.

Palestinian militants have repeatedly promised deadly retaliation. Israeli soldiers have killed at least 30 Palestinians while losing 2 soldiers during the assaults, Israeli officials