EILAT, Israel — In the first suicide bombing to hit this southern resort, a Palestinian militant killed himself and three Israelis at a bakery yesterday, and the two radical groups that sent him said they were trying to end weeks of Palestinian infighting by aiming their weapons at Israel instead.The Palestinians’ governing Hamas movement praised the attack as legitimate resistance — a position that was sure to hurt efforts to end a crippling economic boycott imposed by the international community.

The attack also jeopardized a two-month truce between Israel and Palestinian militants in the Gaza Strip. Israeli security chiefs met late Monday to discuss a response. “This is a grave incident, it’s an escalation and we shall treat it as such,” said Defense Minister Amir Peretz.

The bombing shattered a quiet morning in Eilat, a Red Sea resort town of 50,000 at Israel’s southern tip near the Jordanian and Egyptian borders. The town is a popular getaway for Israelis because it has been insulated from Israeli-Palestinian violence.

Shattered glass, body parts and blood-splattered pastries were strewn on the sidewalk outside the bakery, alongside bread trays scattered by the blast. Two of the victims were the owners of the bakery.

A relative identified the third victim as Yisrael Zalmalloa, who emigrated to Israel from Peru. The relative, who would give only her first name, Norma, said his parents live in Miami, Florida, in the United States, but had no other details. U.S. Embassy officials in Tel Aviv had no information.

“It was awful — there was smoke, pieces of flesh all over the place,” said Benny Mazgini, a 45-year-old witness.

Eilat resident Yossi Voltinski said he picked up the attacker, who was hitchhiking on the edge of town, shortly before the attack, but quickly grew suspicious because of the man’s heavy clothing on a warm day.

“He was wearing a coat closed tightly and was wearing a hat. He didn’t speak Hebrew. He was very irritable,” Voltinski said. “I then understood that without a doubt this was a hostile person.”

He said he dropped the man off on a side road with few people and quickly alerted authorities. “From when I called the police until the explosion no more than a few minutes elapsed,” he told Channel 10 TV.

Two Palestinian militant groups, Islamic Jihad and the Al Aqsa Martyrs’ Brigades, claimed joint responsibility for the attack. Both groups said they hoped to encourage warring Palestinian factions to end weeks of clashes.

“The operation has a clear message to the Palestinian rivals. It is necessary to end the infighting and point the guns toward the occupation that has hurt the Palestinian people,” a posting on the Islamic Jihad Web site said.

Despite the statements, fighting between the rival Fatah and Hamas movements continued to rage throughout Gaza. Five people were killed in new clashes, officials said, raising the death toll to more than 60 since infighting erupted in December.

On Monday evening, Palestinian Prime Minister Ismail Haniyeh met with Egyptian mediators who have been trying to stop the infighting. A representative of Palestinian President Mahmoud Abbas was also present, Palestinian officials said. Police said a blast near Haniyeh’s home earlier was an accidental explosion of a gas canister.

Arriving in Cairo, Abbas denounced the Eilat bombing, according to the Palestinian WAFA news agency.

Islamic Jihad identified the bomber as Mohammed Siksik, 20, from the northern Gaza town of Beit Lahiya. Relatives said Siksik was an unemployed labourer who was despondent over the death of a newborn daughter from disease and driven to avenge his best friend’s killing in fighting with Israel.

Dozens of neighbours celebrated the bombing at the family’s home. Children held up pictures of Siksik brandishing an assault rifle, and a crowd chanted slogans praising him as a martyr.

Siksik’s mother, Rowayda, said he left home three days earlier and proudly told reporters that she knew of the attack ahead of time.

“He told me: Meeting God is better for me than this whole world,” she said.

But underscoring the divisions in Palestinian society, gunmen from the Al Aqsa Martyrs’ Brigades and Islamic Jihad got into a loud argument, each side claiming Siksik as their own.

The attack was the second suicide bombing in Israel since Hamas won Palestinian parliamentary elections last January. The group, labelled a terrorist group in the West for its anti-Israel ideology, came under heavy criticism for making statements in support of a suicide bombing in a Tel Aviv restaurant shortly after it took power.

Fawzi Barhoum, a Hamas spokesman in Gaza, called yesterday’s attack a “natural response” to Israeli military policies in the West Bank and Gaza Strip. “So long as there is occupation, resistance is legitimate,” he said.

He also said attacks on Israel were preferable to the recent Palestinian infighting. “The right thing is for Fatah weapons to be directed toward the occupation not toward Hamas,” Barhoum said.

Italian Foreign Minister Massimo D’Alema called the bombing “barbaric,” and Britain’s foreign secretary, said “there can be no justification” for such attacks.

In Washington, the White House said it held Hamas-led government accountable for not preventing the attack.

“Failure to act against terror will inevitably effect relations between that government and the international community and undermine the aspirations of the Palestinian people for a state of their own,” the White House said.

The US and European Union have been enforcing a boycott on financial aid to the Palestinian government since Hamas took office early last year. They have demanded the group renounce violence and recognise Israel’s right to exist — conditions Hamas rejects.

Israel has been trying to bolster Palestinian President Mahmoud Abbas in his standoff with Hamas. But a renewal of suicide bombings — which are sharply down from their height four years ago — could derail efforts to revive peace talks.