Smoke billows from the factory site.

An explosion at a fireworks factory in northwestern Turkey on Friday killed four people and injured 97 others, officials said. At least three people were reported missing.

There were 186 workers at the factory outside the town of Hendek, in Sakarya province, Health Minister Fahrettin Koca told reporters.

Koca, who traveled to the area along with two other ministers, said the explosion killed four workers while 97 others were hospitalized. Close to 40 of the injured were later discharged, he said, adding that of the remaining workers, just one was in critical condition.

Four people were killed in the explosion while 97 others were hospitalized with injuries, Health Minister Fahrettin Koca tweeted. He said 85 ambulances, two air ambulances and 11 rescue teams were sent to the area.

News reports said three workers were in serious condition. 

Several firefighters and ambulances were sent to the factory, which is away from residential areas. However, explosions were continuing, hampering efforts to bring the fire under control. 

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The cause of the blast wasn't immediately known.

Earlier, television video showed a large, mushroom-shape cloud of smoke rising from the factory.

HaberTurk television said authorities blocked roads leading to the factory. Families rushed to the site for news of their loved ones.

Associated Press