SOFIA, Bulgaria — Israel vowed to strike back at Iran for a brazen daylight bombing Wednesday that killed at least seven people on a bus full of Israeli tourists in Bulgaria.
The bombing was the latest in a series of attacks attributed to Iran that have targeted Israelis and Jews overseas and threatened to escalate a shadow war between the two arch-enemies. Iran has denied involvement in the past but did not comment on Wednesday's attack.
President Barack Obama termed it a "barbaric terrorist attack" and called Israeli Prime Minister Benjamin Netanyahu to pledge U.S. help in finding the perpetrators.
The blast gutted the bus at the airport in the quiet Black Sea resort city of Burgas, some 250 miles east of the capital, Sofia, where the Israelis had just arrived on a charter flight from Tel Aviv carrying 154 people, including eight children.
Black smoke billowed into the sky from the stricken bus after the bomb exploded. Young Israelis said they were just boarding when the blast ripped through the bus in the airport parking lot. Israeli Foreign Minister Avigdor Lieberman said at least seven people were killed.
No group immediately claimed responsibility for the attack, which wounded 30 others. But suspicion immediately fell upon Iran and its Lebanese proxy, the Hezbollah guerrilla group.
"All signs point to Iran," Netanyahu said. "Israel will react forcefully to Iran's terror."
The violence came against the broader backdrop of the international standoff with Iran over its nuclear program. Israel has repeatedly hinted it is prepared to strike Iranian nuclear targets if Tehran does not curb its suspected program.
In the past, Iran has accused Israel of being behind a series of covert attacks on Iranian nuclear targets, ranging from the assassinations of Iranian nuclear scientists to mysterious computer viruses that have damaged Iranian centrifuges.
Israel has never admitted to involvement, but it and others have accused Iran of reprisal missions.