Tensions are high between Israel and Iran after Israel blamed Iran-backed Hezbollah for a deadly attack in Bulgaria on Wednesday that left seven people dead.

Five Israelis, along with a Bulgarian driver and the suicide bomber were killed in the attack on a bus carrying Israeli tourists outside the airport in the Black Sea resort town of Burgas.

The bomber has been identified in video footage as a lanky, long-haired man apparently in disguise as an American backpacker. The man was wearing plaid shorts, wearing a baseball cap, and carried a fake Michigan driver's license, Bulgarian officials said Thursday.

Officials on Thursday were trying to identify the bomber using DNA samples, The Associated Press reports.

Israeli Prime Minister Benjamin Netanyahu quickly put the blame on Hezbollah, the Lebanese Shiite militant group which is supported by Iran, and threatened harsh retaliation.

Netanyahu said Iran and Hezbollah "attack and murder innocent citizens, families, young ones, children, people who went for an innocent vacation and whose sin is to be Israeli and Jewish."

Burgas is a popular holiday destination for Israelis.

Israel has blamed Iran for a number of attacks against its citizens in recent months, though Iran has denied the accusations.

On Thursday, Netanyahu said Iran is the source of a "wave of terror" and should not be permitted to have nuclear weapons.

Bulgarian television broadcast footage Thursday of a long-haired man walking in and out of the bus terminal just prior to the explosion, carrying a large backpack.

According to reports from officials, the bomb exploded in the luggage compartment of the bus, as numerous travellers milled around, along with the bomber himself.

Tsvetan Tsvetanov, Bulgaria's interior minister, said the bomber was believed to be about 36 years old and had been in the country for four to seven days.

"We cannot exclude the possibility that he had logistical support on Bulgarian territory," he said.

Bulgarian Prime Minister Boiko Borisov told reporters that U.S. officials said there was "no such person in their database” matching the identify of the person on the driver’s licence.

Other reports have emerged that the bomber was a former Swedish citizen named Mehdi-Muhammer Ghezali, who spent two years in Guantanamo Bay, thought those reports have not been confirmed.

On Thursday, Iran's state TV said it was "ridiculous" for Israel to blame the nation for the Bulgarian attack.

However, Iran's ongoing rhetoric against Israel is taken by many as proof the nation wouldn't be opposed to supporting terrorist acts against Israel.

Iran claims Israel's Mossad spy agency has been behind the slayings of at least five nuclear scientists since 2010, as well as planting a powerful computer virus named Flame in the country's nuclear control computers -- a charge Israel has not denied.

In fact, Israeli leaders have often said all options are on the table when it comes to neutralizing the threat posed by Iran.

Speaking to CTV News Channel from the Israeli city of Herzliya, Middle East analyst Meir Javedanfar said that although Iran is “one of the credible suspects, we have to wait for (an) investigation before we can say conclusively that Iran was responsible.”

He suggested that al Qaeda could also be responsible.

According to Javedanfar, the repercussions of Israel’s allegations regarding Wednesday’s bombing are likely to be minimal.

“I don’t think this is going to create a war between the two countries,” he said.

In Berlin, German Foreign Minister Guido Westerwelle called on Israel Thursday to exercise caution until "the real perpetrators and backers" are found.

In Washington, the blast was condemned strongly and White House press secretary Jay Carney said the U.S. "commitment to Israel's security remains unshakeable."

With reports from The Associated Press