Russia ? President Dmitry Medvedev on Saturday demanded that Russia tighten its notoriously lax fire codes after the deadliest blaze since the Soviet era killed at least 107 people celebrating in a nightclub with a decorative twig ceiling and single exit.

About 130 people were injured, dozens critically, when onstage fireworks set the ceiling of the Lame Horse nightclub ablaze soon after midnight, witnesses and officials said. Many victims were trapped in a panicked crush for the exit as they attempted to escape the flames and thick black smoke.

Authorities quickly arrested two registered co-owners of the club, its managing director, and two other suspects. One other suspect was injured in the fire and remains in critical condition.

Officials said club managers had ignored repeated demands from authorities to change the interior to comply with fire safety standards. Emergency Situations Minister Sergei Shoigu told Medvedev by videoconference from Perm that the club managers violated the law by running the fireworks display that triggered the fire.