Fire triggered a series of explosions at a fireworks factory that set off a major alert in the Sofia region on Thursday.

An interior ministry official told BNT public television that two people had been injured in the explosions at Elin Pelin on the outskirts of the Bulgarian capital.

Interior Minister Kalin Stoyanov said two or three more workers were reported to have been in the pyrotechnics depots at the time of the blasts.

Television images showed a long series of fireworks explosions and clouds of grey smoke rising more than two hours after the initial blast at Elin Pelin, just outside Sofia.