'Three bombs were dropped on a military airfield belonging to Tbilaviastroi plant. There were no casualties,' Mr Shota Utiashvili, the head of the Georgian Interior Ministry's information department, told Reuters.

The plant has been producing Sukhoi Su-25 ground fighters since Soviet days.

He corrected his earlier information that Tbilisi's international airport had been the actual target.

Reuters correspondents working in Tbilisi heard the three loud bangs shortly after 0530 (9.30am).