MOSCOW -- A total of 64 people have been confirmed dead in a major fire that broke out at a four-storey shopping mall in Kemerovo city in southwestern Siberia on Sunday, the Russian Investigative Committee said on Monday.

The fire, which erupted on Sunday afternoon, was reported to have been put out by Monday morning after burning for a whole night. Yet video footage showed smoke still rising from the building in the afternoon.

The conflagration, one of the deadliest tragedies in the country in recent years, was believed to have started on the shopping mall's fourth floor, which housed a cinema and children's play area, according to Russian Emergency Services Ministry.

Totally, 25 victims have been identified, including 13 children aged 4-13, said Russian Health Minister Veronika Skvortsova. Witnesses told local media that many children who were watching kids' movies in the mall's cinema were killed.

Minister of Emergency Situations Vladimir Puchkov said he expected 64 to be "the final figure of deaths."

However, the exact number of the missing is still unknown. Previous reports said 64 people were missing, including 41 children.

Rescuers are struggling to reach the upper floors because the roof of the four-story building collapsed.

A total of 663 people took part in the search and rescue operation, the Emergency Situations Ministry said, adding that their work has been complicated by strong gas contamination, high temperatures and dense smoke.