(QHA) -

An explosion and fire have rocked a chemical plant outside a separatist stronghold city of Donetsk in eastern Ukraine. Rebels say it was hit by government shelling.

No casualties or damage were immediately reported from the blast which was so powerful that it was heard as far as downtown Donetsk.

An armed conflict between Russia-backed separatists and government forces has killed more than 5,300 people and displaced more than a million.

The rebel mouthpiece Donetsk News Agency said on Monday that the chemical plant to the west of the city was hit by a Ukrainian artillery shell but the fire was put out and it posed no danger.

The rebel stronghold of Donetsk lies in the middle of the Ukrainian industrial heartland, and explosions like this have long been feared.