It remains unclear how the fire started on the third floor. Pictures clearly showed pro-Ukrainians throwing Molotov cocktails towards the floor.
But Serhiy said he saw someone "on the third floor throw a Molotov cocktail through the closed window. However, the glass didn't break and a fire started inside".
People struggled to get out of the smoke-filled floor. One survivor told Russia Today: "We couldn't go down, we were seeing people from other floors being brought down and then those rioters down there attacked them like a pack of wolves."
But other eyewitness reports,
for example in the Kyiv Post, said pro-Ukrainian activists rescued dozens of people from the burning building.
Some people got to ledges and were helped by ambulance ladders. Some fell. Some people were reported to have shouted "die" as people fell.
One of those who had been at the building, Anatoly, said the people inside were not "pro-Russian activists".