- 30 updates
The Bulgarian President Rosen Plevneliev was quoted by the national news agency as saying that he received no advance warning of an expected attack when he held a meeting with Israel's intelligence agency, Mossad, last month.
He said that the two countries' intelligence agencies share a good relationship and that he would have acted on any lead.
US President Obama called Israeli Prime Minister Netanyahu earlier today to offer his condolences.
Barack Obama added his name to world leaders who have condemned the deadly attack on a bus carrying Israeli tourists in Bulgaria.
"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," Obama said in a statement, calling the attack "completely outrageous."
Six people have been killed in the blast that ripped through a bus carrying a group Israeli tourists. It is now believed that the explosion was caused by a bomb in the bus itself. Bulgarian Foreign Minister Nikolai Mladenov said: "The explosion was caused by a bomb in the bus."
In a statement, the foreign ministry said five people were killed and one died later in hospital. Thirty two people in total were taken to hospital with injuries.
White House spokesman Jay Carney said that the US condemns the attacks in Bulgaria and said the people of America stand with the people of Israel and Bulgaria, he added, "of course our commitment to Israel's security remains unshakeable."
The United States Ambassador to the UN has tweeted reaction to the blast in Bulgaria:
Bulgarian Foreign Minister Nikolai Mladenoc says that the airport explosion was caused by a bomb on a bus.
Latest ITV News reports
World leaders have called for justice after a bomb left at least six Israelis dead and injured 30 at Burgas Airport in Bulgaria.