Austrian Chancellor Sebastian Kurz has offered condolences to the bereaved families over the tragedy in Kerch Polytechnic College and wished a speedy recovery to those injured.

"My thoughts are with the families of the victims of the horrible Kerch college school shooting. I wish all of the injured a speedy recovery!" Kurz tweeted.

On October 17, a Kerch Polytechnic College student opened fire there, carried out an explosion and then committed suicide. Twenty people were killed in the attack, including the attacker, and about 50 people were injured. The criminal case launched under the "Terror Attack" section was reclassified under the "Murder" section.

Three days of morning were declared in Crimea on Thursday.