Pro-Russian fighters ride a airborne self-propelled artillery gun Nona in downtown Donetsk, eastern Ukraine Thursday, July 24, 2014.
The Ukrainian army has reported rebel attacks overnight throughout the restive east, claiming that at one border crossing the rebels were supported by artillery fire from the Russian side.
Ukrainian forces are trying to close in on the rebels, cutting them off from the border with Russia which Kiev believes is the source of arms and reinforcement. Moscow has vehemently denied a role in the conflict between pro-Russian separatists and government troops which has left more than 400 people dead and displaced tens of thousands.
In a statement on Friday, the headquarters of the government's military operation in the east listed at least seven locations where rebels attacked Ukrainian troops. They also claimed that attacks on two locations including a border crossing were supported by artillery fire from Russia.