KIEV - At least 10 people were killed and 13 were injured when a shell struck a passenger bus at a government army checkpoint in eastern Ukraine on Tuesday, a regional press spokesman said.

The incident occurred near the town of Volnovakha south of the major industrial city of Donetsk, which is the centre of a nine-month conflict involving government forces and separatist fighters.

"Ten people have been killed and at least 13 are wounded," the spokesman said, adding the bus was carrying civilians from the coastal town of Mariupol through the government checkpoint when it was hit.