Moscow, March 26 (IANS): At least 64 people, including many children, perished in the Siberian city of Kemerovo as a massive fire engulfed a crowded shopping mall where there was no alarm and the fire exits had been blocked, the Russian authorities said on Monday.

The inferno ripped through the top floor of the four-storey Winter Cherry commercial complex, which included a three-screen cinema complex, a skating rink and an entertainment centre for children, on Sunday afternoon in Kemerovo, located in southern Siberia around 3,000 km east of Moscow.

Many of the victims were children as the mall's shops, cinema and bowling alley were packed due to school holidays. At least 16 people were still missing and many others were hospitalised, the Russian media reported.

A video on social media showed plumes of smoke billowing from the mall's roof and windows. Other videos showed people jumping from windows to escape the flames and smoke. According to one official, the temperatures within the mall at the time had reached 700 degrees Celsius, the RBC news outlet reported.

The fire engulfed a children's trampoline room and a cinema hall on the fourth floor.

Russia's Investigative Committee (ICR) in a statement said it had opened a criminal investigation into the cause of the fire. It said a fire safety technician at the complex "switched off the alarm system" after being alerted about the fire.

Speaking to the relatives of the missing, Kemerovo region's deputy governor Vladimir Chernov said the fire had started in the children's entertainment room on the fourth floor, where there was a trampoline with foam rubber.

"The preliminary version is that one of the children had a lighter," Chernov told the relatives, according to Interfax. "The fire started from the trampoline pool, filled with foam rubber, which got lit up as gunpowder."

Chernov said that the fire alarm did not work and that the cinema hall's doors were shut. However, Rossiya 24 TV, a national broadcaster, said an electrical fault was the most likely cause.

Russian Deputy Emergencies Minister Vladlen Aksyonov said: "Two out of three cinema halls caved in from the fourth to the third floor of the building."

The committee said four people were detained for questioning including two fire safety officials and Winter Cherry complex's technical director.

In a Facebook post, Kemerovo politician Anton Gorelkin said that "fire exits were shut, turning the complex into a trap" and "there was no organised evacuation".

The fire was extinguished on Monday but Emergencies Minister Vladimir Puchkov said that the rubble started to smoulder due to the multilayer floorings in the building.

Firefighters said smoke was billowing out and the remaining structures were at risk of collapse. Some 1,500 square metres of the 23,000 square metre mall were destroyed.

Two witnesses told the BBC that they had seen the fire blazing in the trampoline room but had not heard any fire alarm. Witness Anna Zarechneva said "a woman burst into the cinema during the film and shouted 'Fire! Fire!', and we started running out".

"The lights didn't come on in there to help us escape... no alarm bells were ringing. I only heard an alarm when I reached the first floor," she said.

A group of children from a school in Terescevsky were at a movie theatre near the centre of the blaze. According to the local KP News, some of the trapped children called their families from inside the theatre.

Kemerovo region declared three days of mourning and locals left flowers and toys at a makeshift memorial near the complex.

President Vladimir Putin expressed his condolences to the relatives of the victims in the fire tragedy that underscored an appalling record of fire safety in Russia in recent years.