Bomb Rips Apart Israeli Bus, Kills 22 in Bold Terrorist Attack : Mideast: Deadliest assault in 16 years stuns Jewish state. Hamas claims responsibility and threatens to strike again. Officials vow crackdown on Palestinian extremists.

A powerful bomb, apparently placed by Islamic militants opposed to the Arab-Israeli peace negotiations, blew up a crowded bus during the morning rush hour in the heart of Tel Aviv on Wednesday, killing 22 people and wounding 48.

The explosion lifted the bus off the pavement and scattered charred bodies of passengers--many of them dismembered--up and down Dizengoff Street, turning cosmopolitan Tel Aviv’s central thoroughfare into a slaughterhouse.

“People went flying into the air, arms and legs thrown in different directions,” said Moshe Reiner, who was walking to work when the blast occurred at 8:55 a.m. “It was a very terrible thing. There are no words, really, to describe the horror we saw.”

The death toll was the highest in any terrorist attack in Israel in 16 years.

The Islamic Resistance Movement, known as Hamas, said in Amman, Jordan, and in telephone calls to local radio stations that it was responsible for the bombing, its third and most devastating attack in Israel in two weeks. Hamas opposes the year-old peace accord between Israel and the Palestine Liberation Organization and has vowed to carry its fight into Israeli cities.

In an earlier statement read at noontime prayers in mosques in the Gaza Strip, where Hamas has strong support, the group’s military wing known as the Izzidin al-Qassam Brigades declared there would be more attacks.

“God will torment them with your hands and the hands of the faithful,” the Al-Qassam statement said, calling the Tel Aviv bombing revenge for the killing of three Hamas members after they kidnaped and subsequently shot dead an Israeli soldier last week. Hamas gunmen had earlier killed two people in Jerusalem’s cafe district.

Prime Minister Yitzhak Rabin, who cut short a visit to London and convened an emergency meeting of his security advisers on his return, vowed to hit back hard at Hamas, saying he would seek legislation broadening the powers of Israel’s security police to hunt down its leaders, detain them without charge and use harsher methods in interrogating them.

Comments by Rabin and other top Israeli officials indicated that a major roundup of Hamas supporters was planned for the West Bank, in Arab East Jerusalem and, with or without the cooperation of PLO Chairman Yasser Arafat, in the Gaza Strip, where Palestinians have self-rule.

“Ways need to be found so that suiciders, the murderers of Hamas, will know that they are not the only ones who can be killed in their operations, but also their houses, the houses of their families, could be harmed,” Rabin said. “Certainly, I cannot find the words to express the pain and anger at the murderous attack against innocent civilians in the heart of Tel Aviv by the Hamas organization.”

President Ezer Weizman, visiting the injured in Tel Aviv’s Ichilov Hospital, said the Tel Aviv bombing would “require an unusually harsh reaction--different from what has been done so far.”

“This cannot be allowed to continue,” Weizman said. “We will have to catch (Hamas members), to tear them apart, to chop them to pieces. This is what I’m certain the Israel Defense Forces and the security service will do.”

Israel quickly closed its frontiers with the Gaza Strip and the West Bank on Wednesday, barring Palestinians from crossing into Israel to work. And Rabin said that, in the long term, “We need a separation between us and the Palestinians, not just for days but as a way of life.”

Rabin declared, however, that Israel will continue to pursue peace with the Palestinians and its other Arab neighbors--but demand that they take tougher actions against Hamas.

“What the Islamic movements are fighting is not the peace process,” an angry and exhausted Rabin said, “but the very existence of the state of Israel for they see the peace process securing Israel’s existence.”

Even victims of the bombing agreed. “The peace process has claimed a heavy price, but I think we have to continue with it and not stop,” said Shmulik Sadan, 28, who was on his way to work and reading his newspaper at the back of the bus when the explosion occurred. “Every time, it hurts again. But if we don’t make peace, it will just get worse and worse.”

Arafat called Foreign Minister Shimon Peres to convey his condolences and offer assistance in finding those responsible for the bombing. Other Palestinian ministers condemned the bombing as brutal terrorism intended to halt the peace process.

“Pushing forward the peace process is a major part of responding to the actions of extremists who receive instructions, training and funding from known external parties,” Arafat said in a statement denouncing the attack.

Israel contends the PLO has done too little to prevent violence by the Islamic groups, and Rabin and Peres said they will make “new demands” of Arafat in his ongoing negotiations with Israel to ensure its security.

In Washington, President Clinton denounced the bombing as “an outrage against the conscience of the world” and said he will still travel to the Middle East next week to witness the signing of a peace treaty between Israel and Jordan.

The President said in a written statement that the bombing was “aimed at destroying the hopes of the Palestinian people as surely as it is directed at the people of Israel.” He urged other world leaders to condemn the attack and “ensure that there is no haven or support for those responsible.”

The attack along a street that for many Israelis symbolizes the good life reminded the country of its continued vulnerability to terrorism even as it expands its peace agreement with the Palestine Liberation Organization and prepares to sign a full peace treaty with Jordan.

“It was a blow that went straight to our heart,” Tel Aviv Mayor Roni Milo said. “This terrible catastrophe, and its location, tears us to shreds.”

The bombing was the deadliest attack in Israel since March 11, 1978, when 37 Israelis died in a series of bus and car hijackings by Arab gunmen.

On Wednesday, Lt. Gen. Ehud Barak, the Israeli armed forces’ chief of staff, said a suicide bomber apparently boarded one of the Dan Bus Co.’s No. 5 buses with up to 45 pounds of explosives, waited for the bus to fill with passengers and then set off the bomb as a second bus drew close in the heart of Tel Aviv.

“All of the sudden I heard such a big boom that I thought a plane had crashed,” said taxi driver Shlomo Ben-Nun, 39, who was about 50 yards ahead of the bus when it exploded--and “escaped with my soul within me.”

The first explosion seemed to be followed by others and by a fireball that engulfed the bus, witnesses said. Briefly, there was silence, and then there were screams, sobbing and sirens of rescue vehicles. Many people fled in panic.

Police officers sent to deal with the blast wept at the carnage they saw strewn over the street.

“People flew from the sidewalk, and the head of the driver was completely cut off,” Eitan Yamini, another witness, said. “I saw immediately that there were 15, even 20 dead from the bus and the sidewalk. Even a war zone would not look like this.”

Many bodies were in pieces so small that black-coated men from the Hevra Kadisha, Israel’s burial society, had to pick gently through the wreckage to find them. Arms and legs were found on the rooftops of four-story buildings. Eight hours were needed to identify just the first six victims, whose bodies were largely intact.

Police believe a West Bank Islamic militant, Yeyeh Ayyash, known as “The Engineer,” who has been wanted for two years in connection with other bombings, was involved in Wednesday’s attack.

Some of the injured passengers recall a man with dark hair, perhaps in his 30s, and carrying a big bag who was seated in the fifth row--the area where police experts believe the bomb was--but nobody regarded him as suspicious.

Police have not ruled out the possibility that the bomb may have been planted on the bus earlier and set to detonate during rush hour to maximize the number of casualties.

Police said the Tel Aviv bomb was similar in strength to a Hamas bomb that killed five Israelis at Hadera in April; a Hamas suicide bomber killed eight Israelis at Afula the same month.

Angry Israelis called for retaliation against Palestinians and demonstrated here and in Jerusalem on Wednesday evening. “Death to the Arabs, death to Rabin,” they chanted at Zion Square in Jerusalem, where they scuffled with police.

Tel Aviv Mayor Milo pleaded for calm in his city. “I understand the cries of fury, but we have to say calm,” Milo said. “This won’t bring anyone back to life.”

Benjamin Netanyahu, chairman of the opposition Likud Party, warned that if Rabin did not get tougher with the Palestinians he would be “personally responsible for a wave of disasters that will follow.”

Times staff writer Parks reported from Jerusalem, researcher Hauser from Tel Aviv.