Explosion on Bulgaria Tour Bus Kills at Least Five Israelis Damaged buses at Bulgaria's Burgas airport on Wednesday after at least six people were killed and dozens more were wounded by an explosion on a bus carrying Israeli tourists outside the airport. BURGAS, Bulgaria - A tour bus carrying beachbound Israeli vacationers exploded in a fireball on Wednesday outside an airport in the Bulgarian city of Burgas, killing at least six people and wounding dozens more in what Bulgaria, Israel and the United States called a terrorist bomb attack. Israel quickly blamed Iran and promised a firm response. Witnesses quoted by Israeli news media said some victims were on fire as they tried to escape the bus. They said that many suffered severe burns and that body parts were flung around the parking lot. Iran had no immediate comment on Israel's accusations, and no group claimed responsibility for the blast, which the Bulgarian foreign minister said had been caused by a bomb placed in the bus's luggage compartment. But if the Israeli accusations are confirmed, the Bulgarian blast would be the first successful attempt by Iranian operatives to kill Israelis in attacks abroad after a string of failed bomb plots targeting Israeli diplomats in Georgia, India and Thailand this year. Even without such confirmation, the Bulgarian explosion escalated the tensions between Israel and Iran that are already high because of the Iranian nuclear energy program, which Israel has called a guise for Iran to develop nuclear weapons despite Tehran's repeated denials. The explosion came only a few days after a suspected operative of Hezbollah, the Lebanese militant group with close ties to Iran, was arrested in Cyprus on suspicion of plotting to kill Israeli tourists there. That was big news in Israel and reinforced the sense of suspicion that Israelis vacationing abroad might be targets. Still, the deputy foreign minister of Israel, Danny Ayalon, was quoted on Israel's Channel 2 television as saying there was no warning of the Bulgaria attack. The Bulgarian Foreign Ministry said on its Web site that the country's president, foreign minister and interior minister rushed to the scene and that the authorities were working on the theory that the explosion was a terrorist attack but did not specify who might be responsible. In the capital, Sofia, home to most of the 5,000 Bulgarian Jews in the overwhelmingly Christian country of more than seven million, the mayor ordered police deployments in all public places linked to the Jewish community, The Associated Press reported. In Washington, President Obama said in a statement that he strongly condemned "today's barbaric terrorist attack on Israelis in Bulgaria," but he did not specifically accuse Iran. In what appeared to be an Obama administration effort to reinforce his support for Israel, which Mr. Obama's Republican adversary, Mitt Romney, has called into question, the White House also said in a separate statement that Mr. Obama had called Prime Minister Benjamin Netanyahu to offer his condolences, and had "pledged to stand with Israel in this difficult time, and provide whatever assistance is necessary to identify and bring to justice the perpetrators." The Bulgarian Foreign Ministry said at least six people had died and 30 had been wounded. At least four victims suffered burns and shrapnel wounds, a local hospital official said. Mr. Netanyahu convened security consultations after the bus explosion, which he called a "terror attack in Bulgaria." "All signs point to Iran," Mr. Netanyahu said in a statement. He and other Israeli officials noted that the explosion came on the 18th anniversary of a bombing of an Argentine Jewish center in Buenos Aires that killed 85 people and wounded hundreds, an attack for which Argentine prosecutors have blamed Iran. Iran, which does not recognize Israel's right to exist and has sometimes referred to Israel as a Zionist plague on the Middle East, has blamed Israeli agents for a string of assassinations of Iranian nuclear scientists over the past five years, for which Iran has vowed revenge. Israel has never confirmed or denied responsibility for those assassinations. Reporting was contributed by Jodi Rudoren, Gabby Sobelman and Isabel Kershner from Jerusalem, and Rick Gladstone from New York.