"I can definitely say that the attack was plotted, prepared and implemented by people who are very far away from Bulgaria," Ministry Chief of Staff Kalin Georgiev told Bulgaria's 24 Hours newspaper in an interview.
- Report: Agents study possibility Burgas bomber was British
Qaedat al-Jihad claims responsibility for Burgas attack
Bulgaria releases photo of suicide bomber
"They come, act and leave," he said. "We also cannot talk about so-called homegrown terrorism. The people who prepared the attack did not use local criminal infrastructures for logistic support," he added.
The bomb itself, however, was likely assembled on Bulgarian soil, Georgiev noted. "There is nothing specific about its make. Our experts estimate that it was assembled somewhere close as no one would risk carrying an activated improvised explosive device (IED)," he said.
The bomb's components were legally available in any shop both in Bulgaria and abroad, he added.
Discovering the bomber's identity was now "a prime task of the investigation," which was progressing, albeit slowly, Georgiev said.
On Wednesday, Bulgarian authorities released a computer generated image of the terrorist; his severed head, which was found on the scene of the attack, was used to compose the image.
Prosecutors said last week they were working with the authorities in Belgium, Britain and Finland in an effort to identify the suspect's origin.
Seven people were killed, five of them Israelis, and 34 people were injured, when a blast tore through a bus shuttling Israeli tourists in the terminal of Sarafovo Airport last month.
- Receive Ynetnews updates
directly to your desktop