Posted on August 26, 2014
The incident comes ahead of a key meeting between the Ukrainian and Russian presidents.
Petro Poroshenko and Vladimir Putin are at a summit in Minsk in Belarus.
More than 2,000 people have died in months of fighting between Ukrainian forces and separatists in the Donetsk and Luhansk regions.
The two regions declared independence from Kiev following Russia’s annexation of the southern Crimean peninsula from Ukraine in March.