A daytime bombing that killed seven people and injured dozens on a bus full of Israeli tourists was most likely a suicide attack, Bulgarian officials said on Thursday. Israel stood by its claim that Hezbollah was responsible and vowed to hit back.

An Israeli survivor is carried on a stretcher to an ambulance after leaving a hospital in the city of Burgas, Bulgaria, on Thursday, en route to Israel. Seven people, including five Israelis, were killed and dozens were injured in a bombing on a bus transporting tourists at a Bulgarian airport. Israel vowed to find those responsible and punish them. [Photo/Agencies]

The identity of the suspected bomber was still unknown but a Michigan driving license that he carried was a fake, Bulgarian Prime Minister Boiko Borisov said.

"We worked on this with colleagues from the FBI and the CIA," Borisov said. "They said that there is no such person in their database."

The suspected bomber appeared on security camera tape for nearly an hour before the attack, which gutted the bus at the airport in the quiet Black Sea resort of Burgas, 400 km east of the capital, Sofia.

"The site is still under investigation," Interior Minister Tsvetan Tsvetanov said. "Our main goal is to gather the necessary evidence."

The Israelis had just arrived on a charter flight from Tel Aviv carrying 154 people, including eight children. Young Israelis said they were just boarding when the blast ripped through the white vehicle in the airport parking lot.

Officials lowered the death toll to seven after mistakenly reporting that someone had died overnight. The death toll now includes five Israelis, the Bulgarian driver and the suspected bomber.

No group has immediately claimed responsibility, but suspicion fell upon Iran and the Hezbollah guerrilla group. Iran's state TV rejected accusations of Teheran's involvement, saying in a commentary on Thursday that claims by Israeli Prime Minister Benjamin Netanyahu and others were "ridiculous" and "sensational".

No advance intelligence

"The direct executors are Hezbollah," Israeli Defense Minister Ehud Barak said on Thursday. "Israel will do all it can to find those responsible and punish them, both those who carried it out directly and those who dispatched them."

The Israelis have long threatened to resort to military force to curb Teheran's disputed nuclear program, but Barak sounded more restrained after the attack, Reuters reported, saying his response suggests covert action against individuals.

Despite repeated alerts and concerns about an Iranian-backed attack in recent months, Israel said it had no advance intelligence on a pending attack in Bulgaria.

The bombing was the latest in a series of attacks attributed to Iran that have targeted Israelis and Jews overseas and threatened to escalate a shadow war between the two countries.

Israel said a military plane carrying 33 Israelis injured in the bombing left Burgas for Israel, where they will be taken from the airport to the hospital. A Bulgarian government plane will fly 100 other Israelis, who were not wounded but who wanted to cut short their vacation, back to Israel.

The Burgas airport was closed and traffic redirected. In Sofia, Mayor Yordanka Fandakova ordered a stronger police presence at all public places linked to the Jewish community. Some 5,000 Jews live in Bulgaria, most in the capital.

AP-Reuters