At least 109 people were killed and dozens injured overnight to Saturday when a blaze sparked by indoor fireworks swept through a nightclub, in one of the deadliest tragedies to hit Russia in recent years.
Flames ripped through the Lame Horse nightclub in the Ural city of Perm as around 230 people celebrated the popular venue's eighth anniversary, local police said, quoted by Russian news agencies.
Russian television showed bodies being piled up outside the club by rescue workers. The windows of the one-story building were shattered and charred.
Local residents told AFP the fire could have spread quickly because a barn theme meant the club was decorated with highly flammable straw panels.
Russian authorities said they had arrested the owner and manager of the club on Saturday.
Emergency Services officials in a televised meeting with President Dmitry Medvedev said managers at the venue had violated fire safety laws and repeatedly ignored orders to comply with standards.
"Warnings were issued, but they didn't react," Medvedev said, urging swift punishment for those responsible. "They have neither brains, nor conscience!"
Premier Vladimir Putin ordered a government commission to probe the causes of the tragedy, saying in a statement: "It is necessary to launch a minute investigation, punish the culprits and discovered the causes of this monstrous disaster."
The death toll from the tragedy reached 109 after another seven burn victims died in hospital, a spokesman for local investigative committee said, quoted by news agencies RIA Novosti and Interfax.
Some 200 relatives of the victims waited in anguish outside a morgue on the outskirts of the city for the slow work of identifying the bodies. A regional emergency situations ministry spokeswoman told AFP so far 57 people had been identified. Related article: Families' agonising wait
She said a further 130 people were injured in the blaze overnight from Friday to Saturday, and local residents said hospitals had put out an urgent call for blood donors in the wake of the tragedy.
Many of those killed died of smoke inhalation or were crushed to death as party-goers rushed to flee, officials said.
A local resident, who gave her name only as Nelly, said staff and performers, including a friend's daughter, had for the most part escaped through a back door.
"The lights went out and she crawled out through a back exit. Her clothes were all charred from the fire and black," she said.
"There were fireworks set off at the scene, and one hit the plastic ceiling, setting everything ablaze. People panicked and succumbed to burns, the crush and gas poisoning," the Perm region's public security minister Igor Orlov was quoted as saying.
Officials ruled out the possibility that the tragedy was due to a terrorist attack as FSB security service experts found no trace of explosives or other evidence at the scene.
The tragedy came a week after a train blast on a busy railway from Moscow to Saint Petersburg killed 26 people and renewed fears of terror attacks in Russia's heartland.
A grainy video from inside the club broadcast on Vesti showed the ceiling starting to blaze. Smoke wisped through the crowd of young party-goers with drinks, who slowly realize what is happening and rush toward an exit.
Enforcement of fire safety regulations is known to be lax in Russia, where thousands of blazes are recorded every year and the death rate from fires is several times higher than in the West.
Perm is a city of around a million people and lies about 1,200 kilometres (700 miles) east of Moscow in Russia's Ural mountains.