According to new reports, the fire lead by an explosion was caused by pyrotechnics. Most of the people died due to burns or gas inhalation.
TV news reports show the charred bodies of the victims, majority of whom were youngsters, lying in rows outside the club.
ITAR-Tass news agency quotes Regional security minister Igor Orlov as saying that the club had a suspended plastic ceiling that caught fire when 'cold fireworks' were ignited.
These fireworks are generally are fountain-type displays with lower temperatures than conventional fireworks.
The authorities have ruled out the possibility of a terrorist attack.