Bomb placed in trunk of bus with at least 40 people on board was detonated near Burgas airportIsrael has accused Iran of ordering a fatal bomb attack on an Israeli tour group in Bulgaria, in which at least six tourists were killed and 33 injured, three critically.A group of about 200, mostly young Israelis, travelling with the Kavei Chufsha tour company had just flown into the country and were being driven to their hotels in a convoy of three coaches when the explosion hit one of them in the Black Sea city of Burgas, 250 miles (400 kilometres) east of the capital, Sofia.The bomb was detonated not far from Burgas airport, said Dimitar Nikolov, the city's mayor. At least 40 people were on board when it exploded. Little more than an hour after the attack, the Israeli prime minister Binyamin Netanyahu issued a veiled threat to Tehran in a brief statement holding it responsible for the attack.," he said.The attack comes days after a 24-year-old Lebanese man affiliated with Hezbollah was arrested in Cyprus on suspicion of planning a terror attack targeting Israeli tourists, based on evidence provided to local police by Israeli intelligence.The man was found with information on tour buses carrying Israeli passengers, a list of Cypriot tourist spots favoured by Israel tourists and details of Israeli airlines that fly into Cyprus, Greek newspaper Phileleftheros reported."Based on the modus operandi of Hezbollah and Iranian agencies, including the Revolutionary Guard, I think a clear trademark connects today's attack with those elements," said Boaz Ganor, executive director at the Institute for Counter-Terrorism in Herzliya.This month's consecutive attempts - one thwarted and one successful - on Israeli targets abroadfollows attacks on Israeli diplomatic targets in India, Georgia and Kenya in February this year. Iran has spoken of its "open war" on Israel."In February, the same groups were identifiable by their trademarks - magnetic bombs stuck to the bottom of diplomatic cars. This same method has not necessarily been used in today's attack, but we are seeing the same technique of simultaneously planned attacks," said Ganor."I would definitely not underestimate the threat of further attacks. There may well be terror units in different countries with similar contingency plans to attack Israeli tourists in the near future."Initial reports claimed the explosion was caused by a suicide bomber, after witnesses reported seeing a person board the bus before it blew up.Michel Parhan, whose daughter Ron was injured in the blast, said she had called her in panic saying that a man had boarded the bus and blown himself up."She sustained cuts and was bleeding, they removed her through the window of the bus," Parhan told Haaretz. "She was hysterical, and is there without a cell phone, so she could not say much.". The Bulgarian interior minister, Tsvetan Tsvetanov, was quoted on national radio BNR as saying the police were investigatingEhud Barak, Israel's defence minister, promised that its security services will do all they can to find those responsible for the attack."We have been tracking the intentions of terrorist groups such as Hezbollah, Hamas, Iranian groups and the Islamic Jihad to carry out attacks across the world for quite some time," he said. "We have a long struggle with them, which includes many successes, as well as difficult days. Today is one of those difficult days. It is important that Israelis continue to travel across the world, continue to travel in Israel and live their normal lives despite all the pain."Bulgarian media reports said an 11-year-old child and two pregnant women were among the injured.Within minutes of the attack, Burgas airport was closed and newly arrived passengers from Israel were not allowed to disembark.Eleven flights from Tel Aviv bound for eastern Europe were also grounded.The Israeli foreign office said Israeli medics had been sent to Bulgaria to assist the injured. As the emergency teams were rallied, Israeli officials focused on those responsible and how the Jewish state should respond.Following a briefing from Nikolay Mladenov, his Bulgarian counterpart, foreign minster Avigdor Lieberman called for a situation assessment.