Ukraine's president says a missile attack on evacuees at a train station in the east of his country shows Russia's "evil has no limits".
Officials say 50 civilians were killed in the strike and hundreds of others were injured.
The Kremlin denies responsibility.
Former military adviser Mark Voyger claims it's a common Russian tactic - intimidation through terror:
"They are trying to put pressure on the Ukrainian populace, hoping that they would somehow subdue... the Ukrainians will yield. It's exactly the opposite. The Ukrainians are getting more and more motivated. They're full of indignation".
