Manhunt under way to find group of armed men who launched attack against Israelis working on security fence, army says.
On the TV website, Iran questions the claims by Israeli Prime Minister Binyamin Netanyahu and others as “ridiculous” and “sensational”.
The website described the Israeli charges as attempts to discredit Iran and its allies such as Syria.
There have been no official statements by Iranian authorities since the Wednesday attack in the Black Sea city of Burgas. Israeli officials and media say the death toll includes six Israelis and one Bulgarian.
|Six Israelis and one Bulgarian killed in blast|
The bombing is the latest in a string of attacks and plots around the world that Israel has blamed on Iran. Iran has denied involvement.
Bulgarian Prime Minister Boiko Borisov says that a Michigan license carried by the suspected suicide attacker in the bombing of the bus carrying Israeli tourists was a fake.
Borisov said on Thursday “we worked on this with colleagues from the FBI and CIA. They said that there is no such person in their database”. He did not release a name.
Borisov says he has asked for the release of a photo of the suspect taken from a security camera from the area before the attack, which gutted the bus at the airport in the Black Sea resort city of Burgas on Wednesday.
Earlier, officials lowered the death toll to seven, including the suspected bomber, after mistakenly reporting that someone had died overnight.
The Israeli Defence Minister Ehud Barak called the attacks as part of the global wave on terror.
“The attack in Burgas was led by members of Hezbollah and sponsored by Iran, the al-Qaeda and Islamic Jihad networks also operate globally,” he added, citing a long list of recent attacks or attempted attacks on Israelis around the world including in Thailand, India, Georgia, Kenya and Cyprus.
US President Barack Obama condemned the attacks in a call with Netanyahu.
“The United States will stand with our allies, and provide whatever assistance is necessary to identify and bring to justice the perpetrators of this attack,” said Obama.
The Israeli foreign ministry said the bus was carrying tourists from a charter flight that arrived from Israel.
Israeli officials said passengers from a Tel Aviv-Burgas flight boarded the bus shortly after 17:00 local time (14:00 GMT) on Wednesday.
“I was on the bus and we had just sat down when after a few seconds we heard a really loud explosion,” Gal Malka told Israel’s army radio.
“The whole bus went up in flames,” she said, adding that the explosion took place near the front of the bus.
Israeli forensic teams who arrived during the night are helping to identify the bodies.
A Hercules jet carrying senior Israeli army officers and trauma surgeons had landed in Bulgaria to help transfer the wounded to the airport for evacuation.
It is expected to land in Tel Aviv on Thursday afternoon, where the wounded will be taken to nearby hospitals.
|CCTV footage from the Burgas airport in Bulgaria|
Images shown on Israeli and Bulgarian media showed smoke billowing from the scene, a parking lot at the local airport, where the Israeli tourists had apparently just landed.
Several buses and cars were on fire near the carcass of the targeted vehicle.
Burgas mayor Dimitar Nikolov, who was at the airport at the time, said the blast ripped through the bus as the tourists who had flown in from Israel were boarding and placing their bags in the luggage compartment, where he suspects the explosives might have been.
“I cannot say if it was an act of terrorism. The blast was very strong and in my view was triggered by a device which was deliberately set,” Nikolov said.
Trita Parsi, of the National Iranian-American Counsel, speaking to Al Jazeera from Washington, says so far Tel Aviv has not produced any evidence proving Iranian involvement.
“Only a half hour after the actual incident, Netanyahu went out and accused the Iranians,” a time-frame which Parsi says does not leave a lot of time to gather evidence.
Bulgaria, an eastern European nation bordering Greece and Turkey, is a popular tourist destination for Israelis.
In January, Israeli public television reported that Bulgarian authorities had foiled a bomb attack when they found an explosive device on a bus chartered to take Israeli tourists to a ski resort.