Bus explosion at Burgas Airport on Wednesday. Photo: www.dnes.bg.

The terrorist who killed five Israeli tourists and a Bulgarian bus driver in July in Burgas, Bulgaria had up to five accomplices, all foreign, according to Bulgarian Interior Minister Tsvetan Tsvetanov.

Tsvetanov told the Bulgarian 24 Chasa daily that it is too early to name any potential suspects. He did state, however, that the July 18 terror attack was plotted outside Bulgaria for a period of a year and a half.

The probe into the identity of the foreign bomber has collected “lots of evidence,” the minister said, according to reports.

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

In September Bulgarian authorities arrested an individual suspected in assisting the suicide bomber who carried out the attacks.

The man had been hiding in a rural forest area near the village of Zvezdets. He admitted to being a member of Al-Qaeda.

Immediately following the attack, Israel directed blame towards Iran and its Lebanese proxy Hezbollah. Iran has denied involvement.