A powerful blast ripped through an explosives plant in northwestern Turkey on Tuesday killing 12 people and injuring four others, officials said.

Footage showed shards of glass and metal scattered outside the plant, where ambulances stood by.

"According to initial reports, 12 employees died and four were taken to hospital with injuries as a result of the explosion" in the Karesi district of Balikesir province, local governor Ismail Ustaoglu said.

Officials said the injured were not in a serious condition.

The blast took place at 8.25am local time (0525 GMT) at a section of the plant which local officials said collapsed under the force of the explosion.

Interior Minister Ali Yerlikaya said the cause of the blast at the factory, which is located away from residential areas, was not immediately known.

"We are trying to find out what caused it," he said.

Authorities ruled out sabotage and prosecutors have launched a thorough investigation.