At least 109 people were killed and 134 injured when a blaze sparked by a firework show ripped through a packed Russian nightclub, triggering a stampede as revellers rushed to escape clouds of toxic black smoke.
The pyrotechnics show went disastrously wrong at the Lame Horse nightclub in the Russian city of Perm late on Friday when stray sparks ignited wicker coverings on the walls and ceiling during a party celebrating the club's eighth anniversary.
As partygoers rushed for the club's one and only door, scores were choked or crushed to death. Medics said many of those hospitalised were being kept alive with artificial respirators and that some had burns of more than 60 percent.
Some of the severely injured have been sent to Moscow.
A clubber who survived uninjured, identifying herself as Svetlana, told Reuters: "Everything was catching fire so quickly as if it was made of hay, it happened in seconds... We could not all get through, everyone was pushing, from all sides."
President Dmitry Medvedev ordered a national day of mourning for Monday Dec 7 and demanded tough punishment for the owners of the nightclub who he said had repeatedly ignored warnings from fire inspectors that the premises were unsafe.
"They have neither brains nor conscience," Medvedev told ministers in a televised meeting, scolding the club's owners for failing to come forward immediately after the disaster.
A Reuters photographer in Perm saw groups of distraught relatives of those feared dead as they trickled into a local morgue for identification. Others - some weeping or smoking nervously - stared blankly at the lists of the dead.
Hundreds of red carnations and candles have been placed around the club on the pavement.
Friday's fire was Russia's most deadly in decades, emergency officials said, and the worst nightclub fire worldwide since nearly 200 people died at a party in Buenos Aires in 2004.
The fire follows a bombing last Friday which killed 26 and injured more than 100 on a train travelling between Moscow and St Petersburg, but Russian officials repeatedly maintained the nightclub fire was not another attack.
"This is not a premeditated murder, but this does not lessen the gravity of the crime," Medvedev said on a video-conference with ministers who were sent to deal with the disaster in Perm, 1,150 km (720 miles) northeast of Moscow.
Interior Minister Rashid Nurgaliyev told Medvedev there was no evidence of a bomb. Russian prosecutors said five employees, including the club's owner and founders, had been detained in a criminal case on suspicion of breaching fire regulations and manslaughter.
The United States said the timing of the disaster so soon after the train bombing made it especially painful: "We are deeply saddened to learn of yet another tragedy striking Russia," the White House said in a statement on Saturday.
The European Union also sent its condolences.
Video footage obtained by Reuters of the disaster showed a merry crowd celebrating with a joyous show presenter suddenly announcing: "Ladies and gentlemen, we are on fire. Leave the hall. Line up in a queue (to exit)."
Then the camera jerkily moved to show fire roaring along the wicker-covered ceiling of the 500 square metre (5400 square ft) club. Many revellers slowly moved to a narrow exit - some still sipping cocktails and smoking.
A few moments later, a stampede broke out as heavy black smoke quickly filled the hall and the crowd of more than 200 guests rushed headlong trying to escape through tiny doors.
Immediately after the fire, dozens of charred bodies were piled on the pavement outside the club as medics moved the injured into ambulances.
Blood-covered women in evening clothes and knee-high black boots lay on stretchers as scores of policemen swarmed around.
Russian officials have in the past blamed poor fire safety standards for high death tolls in fires at orphanages, hospitals and other institutions.
But Friday's disaster was the worst nightclub fire since a blaze in Buenos Aires killed 192 people and injured nearly 1,000 in December 2004. That fire was caused by a flare which set alight a foam covering on the ceiling.
The Kremlin said the Dec. 7 day of mourning in Russia will have flags at half-mast across the nation. Three days of mourning will be observed in Perm, which is Russia's sixth largest city with a population of 1.2 million.