The Israeli government has accused the Iranian-backed Lebanese group Hezbollah of carrying out a bomb attack in Bulgaria yesterday that killed eight people.
A suicide bomber with a fake US driver's licence is believed to have carried out the attack.
Bulgarian special forces obtained DNA samples from the fingers of the bomber and are carrying out checks to identify him.
The eight dead included the Bulgarian driver of the bus and the bomber.
Injuries were sustained by 30 Israeli tourists who flew back to Israel today.
Israeli Prime Minister Benjamin Netanyahu said Tehran was behind the attack and that "Israel will react powerfully against Iranian terror."
The tourists had arrived on a charter flight from Israel and were on the bus in the airport car park when the blast tore through it.
Iran's embassy in Bulgaria has denied Israeli accusations that Tehran was behind the attack.
"The unfounded statements by different statesmen of the Zionist regime in connection with the accusations against Iran about its possible participation in the incident with the blown-up bus with Israeli tourists in Burgas is a familiar method of the Zionist regime, with a political aim, and is a sign of the weakness ... of the accusers," Iran's mission in Sofia said.
The blast came on the 18th anniversary of a 1994 bomb attack in Argentina.
The headquarters of Argentina's main Jewish organisation was struck by a Hezbollah suicide bomber, killing 85 people.
Israeli officials have previously said that Bulgaria, a popular holiday destination for Israeli tourists, was vulnerable to attack by Islamist militants who could infiltrate via Turkey.
Israeli diplomats have been targeted in several countries in recent months by bombers who Israel said struck on behalf of Iran.
