Bulgarian authorities say a blast at the Black Sea airport of Burgas that left seven people dead and more than 30 injured was caused by a suicide bomber.
Interior Minister Tsvetan Tsvetanov told reporters that the bomber had "a fake driving licence from the United States."
Earlier, Bulgarian Foreign Minister Nikolay Mladenov said the blast had been caused by a bomb planted on a bus at the airport, some 400 kilometers east of the capital, Sofia. Mladenov said that Bulgaria "will do everything in its power" to find the perpetrators.
Israeli Prime Minister Benjamin Netanyahu called the incident "an Iranian terror attack" and promised a tough response. The Israeli Foreign Ministry confirmed early on July 19 that at least 31 Israelis had been wounded in the attack and said identification efforts were under way.
Iran has not issued any statement about the attack or the accusations that Tehran was involved.
The July 18 blast came on the 18th anniversary of a deadly attack on a Jewish community center in Argentina. Israel blamed Iran for that attack -- a claim denied by Tehran.
U.S. President Barack Obama offered his condolences to Netanyahu in a phone call and condemned the blast as a "barbaric terrorist attack."
Israeli Defense Minister Ehud Barak said Israel had been monitoring attempts by groups such as Lebanon's Hezbollah, Gaza's ruling Hamas movement, and Iranian and Jihadi operatives to attack Israelis.
"Several hours ago we had a terrorist attack in Burgas in Bulgaria on an Israeli tourist bus," Barak said. "We have several people killed and dozens of wounded people. This is clearly a terrorist attack initiated by probably Hezbollah, Hamas, Jihad or any other group under the terror auspices of either Iran or other radical muslim groups."
Barak vowed to hunt down the perpetrators.
"We are in a continued fight against them; we are determined to identify who sent them, who executed it, and to settle the account," Barak said. "In the meantime, we are determine not top stop living normally and have Israelis visiting, under certain precautions, practically any place that they can make tourism to."
The bus targeted by the blast was transporting tourists who had arrived in a charter flight from Israel. There were 154 people on the flight from Tel Aviv.
Bulgaria is a popular destination for Israeli tourists, and in recent years, Burgas has become a favorite and inexpensive haven for groups of Israeli teenagers taking trips after finishing high school and before their military service.
Based on reporting by Reuters, AP, AFP, and dpa