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.

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.

He said the club managers had been fined twice in the past for breaking fire safety regulations, which he did not specify. Russian clubs and restaurants often cover ceilings with plastic insulation and a layer of willow twigs to create a rustic look, one of many uses of combustible materials in buildings by businessmen who bribe officials to look the other way.

The Lame Horse's managers had been scheduled before the fire to report Monday on their progress fixing the flaws.

"They have neither brains, nor conscience," Medvedev said. "They must face the maximum punishment."

He declared a national day of mourning Monday.

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.

Medvedev demanded that lawmakers draft changes to toughen the criminal punishment for failing to comply with fire safety standards.

Enforcement of fire safety standards is infamously poor in Russia and there have been several catastrophic blazes at drug-treatment facilities, nursing homes, apartment buildings and nightclubs in recent years. The nation records up to 18,000 fire deaths a year, several times the per-capita rate in the United States and other Western countries.

Gennady Gudkov, a senior member of the Kremlin-controlled lower house of parliament, said that toughening criminal punishment won't solve the problem. He told the ITAR-Tass news agency that many fire safety officials are corrupt and often turn a blind eye to violations for money.

Leonid Miroshnichenko, who lost his daughter in the fire, said that he believed the ceiling of twigs and plastic sheeting contributed to the death toll.

"I would like to see the official who allowed this club to open. It was he who killed my daughter," he said.

Video recorded by a clubgoer and shown on Russian television showed partygoers dancing before sparks from pyrotechnic fountains on stage ignited the club's ceiling around midnight. Witness Svetlana Kuvshinova told The Associated Press that the blaze swiftly consumed the twigs.

"People were having fun, and it was the peak of the fun when I looked up and saw flames on the ceiling," Kuvshinova said. "The fire took seconds to spread. It was like a dry haystack."

The footage showed the fire spreading through what appeared to be willow twigs as a host shouted without urgency: "Ladies and gentlemen, guests of the club, we are on fire. Please leave the hall."

"There was only one way out," Kuvshinova said. "They nearly stampeded me."

The video showed people reluctantly heading toward the exit, some of them still holding their drinks and turning back to look at the burning ceiling. Within seconds they started rushing away in panic as flames spread through the hall like a fireball.

"There was only one exit, and people starting breaking down the doors to get out," said a woman who identified herself only as Olga, her face and expensive fur coat smeared with soot. "They were breaking the door and panic set in. Everything was in smoke. I couldn't see anything."

A nightclub fire in the U.S. state of Rhode Island in 2003 killed 100 people after pyrotechnics used as a stage prop by the 1980s rock band Great White set ablaze cheap soundproofing foam on the walls and ceiling. Nightclub fires have killed thousands of people worldwide.

Russia has been on edge since last week's bombing of the high-speed Nevsky Express passenger train midway between Moscow and St. Petersburg, in which 27 people died in the first deadly terrorist attack outside Russia's restive Caucasus republics since 2004. Chechen rebels claimed responsibility for the blast.

Russia's top investigative body said the fire killed 109, while the Emergency Situations Ministry said 107 people had died. The cause for the discrepancy wasn't immediately clear.

Officials said nearly 90 of the more than 130 people injured in the fire had severe burns and scores remained in critical condition. Many of the injured were flown to top emergency hospitals in Moscow and St. Petersburg.

Firefighters were on the scene in downtown Perm one minute after the alarm was called in, the Emergency Situations Ministry said, and they took less than an hour to put the fire out. Most of the dead suffocated or were crushed at the exit, officials said.

Many relatives waited for hours at the Perm morgue, not knowing whether their relatives were dead or alive.

"I'm simply devastated, I can't believe it's happening to me," said Yevgeny Porfiryev, his eyes red from tears after he found his 26-year-old son Timur among the dead.

Emergency Situations Ministry officials called the fire the worst in the nation's post-Soviet history. The previous most deadly blaze killed 63 people at a nursing home in southern Russia in March 2007.