Kyrylo Budanov has led the Hur military intelligence, which has claimed a number of highly-effective strikes against Russia.

How the blaze took hold with such ferocity, killing at least 40 people and leaving many more critically injured, is now a key focus for officials.

The investigation into the fire that killed 40 people will consider whether criminal prosecutions are necessary, officials said.

Families are appealing for information about children as young as 15 who are thought to have been at the bar.