Burgas bombing
Burgas bombingIsrael news photo: Flash 90

The Burgas suicide bomber who left five Israeli tourists and their Bulgarian driver dead in July had up to five foreign helpers, a government minister said Thursday.

The attack, carried out on July 18, blew up two tourist buses in the parking lot outside the Burgas airport. It was planned abroad, and the helpers were deployed locally, Bulgaria's Interior Minister Tsvetan Tsvetanov told the 24 Hours newspaper.

“To date we have no proof that any of them were Bulgarian,” Tsvetanov said, according to the AFP news agency.  He said an investigation has revealed that the attack at Burgas airport was planned over a period of a year and a half.

However, investigators are not yet ready to name a suspect.

“The time has not yet come to voice any concrete accusation against the people or groups who performed this terrorist act,” said Tsvetanov. “We must work with concrete evidence. We have to be very cautious as national security is concerned,” he said.

Bulgaria has been a popular tourist destination for Israelis who flock to its Black Sea resorts. But Bulgarian police have so far released only one computer-generated image of a lone suspect who may have acted as an accomplice, in addition to a composite portrait of the suicide bomber.

Israel has said Iran was behind the bombing, and accused the Islamic Republic of sending its proxy, the Hizbullah terrorist organization, to carry out the operation. It was the deadliest attack on Israelis abroad since 2004.