KIEV - A powerful explosion near a munitions factory rocked the rebel-held city of Donetsk in eastern Ukraine on Monday, breaking windows several kilometres (miles) away, but there was no word of any casualties.

The blast around noon (0900 GMT) showed fire and a column of grey smoke rising high into the sky to the northeast of the city, which is a stronghold for pro-Russian separatists fighting government forces.

A Ukrainian military spokesman denied the explosion was caused by a missile fired by government troops, saying Kiev's forces had nothing to do with the incident.