Authorities in Kyiv say pro-Russian separatists fired missiles at a convoy of buses carrying refugees from the eastern Ukrainian city of Luhansk on August 18, leaving many dead.
Ukrainian military spokesman Andriy Lysenko said the separatists fired Grad missiles and mortars at the convoy when it was traveling near Khyashchuvatye and Novosvitlivka.
Lysenko said "many people" were killed, "including women and children."
He alleged that the weapons were given to the separatists by Russia.
Andrei Purgin, a senior rebel leader in the self-proclaimed Donetsk People’s Republic, denied that separatists were responsible for the missile strike.
Purgin said rebel forces did not have the military capability to send Grad rockets into that territory.
A rebel news outlet had reported earlier that separatists and Ukrainian government forces were exchanging heavy artillery fire on August 18 in the area where the buses had been traveling.
With reporting by Reuters, AFP, and Ukrayinska Pravda