DONETSK, Ukraine (AP) — The speaker in Ukraine's parliament says 32 workers have been killed by an explosion at coal mine in war-torn eastern Ukraine.

Volodymyr Groysman told lawmakers that the accident happened before dawn Wednesday.

Donetsk News Agency, the official mouthpiece for the separatists, cited rescue services official Yuliana Bedilo as saying the explosion was caused by a mixture of gas and air — a common cause of industrial mining accidents.

Bedilo was quoted as saying the incident at the Zasyadko mine in the rebel-controlled city of Donetsk was not caused by shelling. Rescue operations are ongoing at the site of the accident.

The east of Ukraine has been wracked by fighting between government forces and Russian-backed rebels for almost a year, during which more than 6,000 people have been killed.