LISBON, Portugal (AP) — Portuguese authorities suspect international terrorists and arms traffickers are behind a "very professional" theft last week at the country's national armory, the attorney general's office said Tuesday.

The suspicions have prompted the attorney general's office to broaden the scope of its investigation into the theft of hand grenades, 9mm ammunition and possibly other weapons, a statement said.

The armed forces have not made public a full list of what was stolen from the arsenal last Wednesday at the Tancos Air Base, 100 kilometers (60 miles) north of Lisbon.

At the time, Defense Minister Jose Alberto Azeredo Lopes called the theft a "very professional" job. He said criminals broke in by cutting a hole in a perimeter fence and that he had informed Portugal's European Union and NATO partners of the theft.

The public prosecutor will be assisted in the case by police, military police investigators and the National Counter-Terrorism Unit, according to the attorney general's office.

No further details of the investigation will be provided due to Portugal's judicial secrecy law, which forbids the release of information about open investigations.