BURGAS, Bulgaria — Bulgarian investigators worked with the FBI and Interpol Thursday to identify the suicide attacker behind a deadly bombing on a bus carrying Israeli tourists, as Iran denied involvement.

US President Barack Obama described the blast at a Black Sea airport on Wednesday that killed six people plus the bomber a "barbaric terrorist attack" as Israel blamed archfoe Iran and Tehran's "terrorist proxy" Hizbollah.

"The suicide bomber, wearing shorts and carrying a backpack, looked like any other tourist," said Bulgarian Interior Minister Tsvetan Tsvetanov.

A video released showed a white man with long hair — possibly a wig — and sunglasses wandering around the airport in Burgas. Tsvetanov said he appeared to be aged around 26 and that he had a fake driving licence from the US state of Michigan.

The authorities had his fingerprints and had enlisted the help of the US Federal Bureau of Investigation (FBI), Interpol and Europol, to discover his identity, the minister said.

The explosion ripped through the bus as around 50 Israeli tourists arriving from Tel Aviv on a plane carrying 154 people were loading their bags and boarding before travelling to a nearby Black Sea holiday and gambling resort.

Five tourists were killed at the scene while the Bulgarian driver died later in hospital, officials said. Another 30 people were wounded.

Witnesses described how panicked passengers jumped from bus windows and bodies lay strewn on the ground with their clothes torn off as ambulance sirens wailed and black smoke rose over the airport.

"I would have lost my life in a split second, had I not jumped out of the bus' window," survivor Moshe Moseri told the Israeli news website Walla, describing scenes of horror with "corpses on the floor with their arms and legs severed".

Israeli Prime Minister Benjamin Netanyahu said the attack "was perpetrated by Hizbollah, Iran's leading terrorist proxy," describing the Lebanese militia as "the long arm of Iran".

The bombing was part of "a global campaign of terror carried out by Iran and Hizbollah" which had reached "a dozen countries on five continents", he said.

Obama said the United States, Israel's staunchest ally, "will stand with our allies, and provide whatever assistance is necessary to identify and bring to justice the perpetrators of this attack".

Iranian state television said Israel's "ridiculous" accusations were "aimed at creating an anti-Iranian atmosphere" amid rising tensions over Tehran's nuclear drive which the West suspects is aimed at building the atomic bomb.

"The Zionist regime, which is responsible for terrorist acts organised in Lebanon, Palestine and against the Iranian nuclear scientists... is launching baseless accusations against other countries to forget its own terrorist nature," a foreign ministry spokesman said.

The bomber struck on the 18th anniversary of an attack on a Jewish community centre in Argentina that killed 85 people, also blamed on Iran.

Wednesday's attack, the deadliest against Israelis abroad since 2004, also also drew strong condemnation from France, Britain, Russia and other governments.

More than 30 wounded Israelis, including teenagers, arrived back in Tel Aviv Thursday after being flown home by the Israeli air force.

Those who left Bulgaria included a pregnant woman and a girl of around seven or eight years old who was carrying her flip-flop because her right foot was wrapped in bandages.

Many had been taken in wheelchairs to ambulances to board their flight home with many having sustained burns and flesh wounds on their legs and arms. Some still had bloodstained holiday clothes on.

Burgas airport opened again at 6:00 pm (1500 GMT) under heavy security, the AFP reporter said, with all traces of the attack removed, although the site remained off-limits behind police tape.

A cordon was set up 500 metres from the airport building where people had to have all bags checked, and no hand luggage was being allowed on flights.

The charred skeleton of the bus was loaded on to a truck and taken away, as was an adjacent bus that also caught fire in the blast and which had a large bloodstain down its side.

Israel and former communist Bulgaria, which has a 13 per cent Muslim population, enjoy good relations and the Black Sea coast has become a popular holiday spot for Israelis, with almost 140,000 visiting the country in 2011.

In January, Israeli public television reported that authorities in European Union member Bulgaria had foiled a bomb attack when they found an explosive device on a bus chartered to take Israeli tourists to a ski resort.