MOSCOW (AP) — Russia's emergencies ministry says 38 people have been injured in an explosion in a plant manufacturing TNT.

The blast took place Saturday in Dzerzhinsk, 400 kilometers (250 miles) east of Moscow. The cause has not been determined.

The ministry said four of the injured were in serious condition.

The blast broke windows in about 200 residences near the plant, the Interfax news agency cited regional authorities as saying.

Dmitry Krasnov, deputy governor of the region that includes Dzerzhinsk, said earlier on state TV that two people were missing in the blast, but later said that information had not been confirmed.