The blasts, claimed by the Islamic militant group Hamas, killed seven people - including the three bombers - and struck a new blow to the peace process just as hopes were rising for its revival.
Hopes for peace in the region were dealt a further setback early today as at least 12 Israeli soldiers were killed during a failed commando raid north of the Israeli-occupied enclave in southern Lebanon, security officials in Lebanon said.
There was no immediate comment from Israel about the raid, or the fatalities. It was not clear whether Israel's attack, in which several Lebanese fighters also were injured, was ordered in response to the Jerusalem bombings.
At least 192 people, including several American tourists, were also wounded in the bombings, which turned the bustling Ben Yehuda Street walkway of cafes and shops into a chaotic nightmare of broken glass and blood.
The four Israelis killed were identified as two 12-year-old girls, one 14-year-old girl and a 20-year-old man, radio reports said.
The three bombers apparently positioned themselves outside three stores, close enough to make eye contact, and blew themselves up within seconds of each other.
"There were three of us talking, and suddenly I heard an explosion," said Bob Helfman of Detroit, who was sitting at a cafe when the attack began.
"I tried to get up, realizing it was a bomb, but my feet could not even support me, and I fell over. Then I heard another bomb, and everyone started running. No one knew which direction to go in."
With sirens wailing and a charred smell in the air, rescue workers treated some victims on the sidewalk, surrounded by overturned cafe chairs and umbrellas. In a scene that has become all too familiar in Israel, ultra-Orthodox burial squad volunteers searched for pieces of flesh in the debris.
After the blasts, Israel stepped up pressure on Palestinian leader Yasser Arafat for an immediate crackdown on Islamic militants, and sealed its borders with the West Bank and Gaza Strip. A previous closure had been eased only two days earlier, ahead of the planned visit of U.S. Secretary of State Madeleine Albright next week.
That closure was imposed after a double suicide bombing in a Jerusalem market on July 30, which killed 17 people.
In Washington, President Clinton denounced the latest bombings and said Albright would go ahead with her trip. He urged Arafat's Palestinian Authority to "do all it can to create an environment that leaves no doubt that terror will not be tolerated."
Clinton called Israeli Prime Minister Benjamin Netanyahu yesterday to express his outrage and condolences, Netanyahu's office said.
Israel Radio said Netanyahu canceled plans for his security chiefs to meet with Palestinian and U.S. security officials, and a source in Arafat's office said Israel was refusing Arafat permission to travel by helicopter from Gaza to the West Bank city of Ramallah.
The three nail-studded bombs exploded shortly after 3 p.m., when hundreds of shoppers and tourists crowded the pedestrian mall, which is lined with cafes, tourist shops, and American fast food restaurants such as Burger King and Sbarro.
In the tumult, a toddler was rushed into the back of an ambulance. Paramedics splashed water in the face of one weeping man. Blood spattered the facade of the Israel Discount Bank.
Hamas, which has carried out 13 bombings in four years of Israeli-Palestinian peacemaking, claimed responsibility and threatened more bombings unless Hamas prisoners held by Israel were released by Sept. 14.
Arafat condemned the attack, and a senior Palestinian official pledged full cooperation with Israel on security matters. But Netanyahu said the already deeply troubled peace process could not go on unless Arafat crushed Hamas once and for all.
"No peace process can exist when the Palestinian Authority enables the leaders of the terrorists to walk around free with their arms, demonstrations and flags in cities that have become refuges for terrorists," he said.
Palestinian authorities detained two Hamas political leaders in the West Bank last night, arrested eight activists and shut down a Hamas newspaper in Gaza, Palestinian security sources said. But the moves fell far short of the mass arrests Israel is demanding.
Hamas leader Abdel Aziz Rantisi said he did not think Arafat would crack down on Hamas as he did following a spate of suicide bombings in early 1995.
"They know that a crackdown is not for the benefit of the Palestinian people," he told The Associated Press at his home in the Gaza Strip.
"Without a solution for the agony of our people inside and outside and without a return to our homeland, I believe that the bloodshed will continue."
Netanyahu called a meeting of his security Cabinet early today, at which ministers were expected to consider authorizing Israeli troops to carry out strikes in territory under Palestinian control, Israeli radio reports said.
In response to yesterday's attack, Israel resealed the West Bank and Gaza Strip, barring Palestinians from entering Israel. Israel also imposed an internal closure, meaning Palestinians could not travel between towns and villages in the West Bank.
Israel's raid in southern Lebanon early today was apparently spotted by Shiite Muslim guerrillas and Lebanese army troops, who thwarted the operation.
The resulting clashes involving Israeli helicopter gunships and fighter planes took place about 25 miles from an Israeli occupied border enclave in southern Lebanon and some 30 miles north of the Israeli border.
The target of the raid was not immediately clear.
Israel established the zone in 1985 as a buffer against guerrilla attacks. Some 1,500 Israeli soldiers patrol the zone along with some 2,500 allied militiamen.