Moscow - At least 53 bodies have been recovered from a fire that swept through a busy shopping centre in an industrial city in Siberia, Russian news agencies said on Monday.
Many people are also still missing from the blaze that broke out on Sunday in the city of Kemerovo, the agencies quoted emergency services as saying.
A previous toll put the number of dead at 37 with nearly 70 missing, including 40 children.
Images on Russian television showed thick black smoke pouring out of the Winter Cherry shopping centre in the city of Kemerovo, which also houses a sauna, a bowling alley and a multiplex cinema and was packed with people on Sunday afternoon.
READ: 3 children, woman dead in Russian shopping centre fire
"At this time, we can confirm the deaths of 37 people in the fire at the Kemerovo shopping centre", Russia's Investigative Committee said, according to TASS news agency.
Investigators had initially reported five people dead including a child and another 30 people injured and taken to hospital.
As the new death toll was announced, a source in the local rescue services said 69 people including 40 children were reported missing, the RIA Novosti agency reported, while the Investigative Committee said it was "verifying information that 35 people could be missing".
The preliminary findings of the inquiry said the fire started around 11:00 (GMT) in one of the cinema halls and destroyed more than 1 000 square metres of the centre, news agencies reported.
"The roof collapsed in two theatres in the cinema," the Investigative Committee said.
Around 120 people had been evacuated from the burning centre, rescuers said.
"This shopping centre on several floors was packed with people mid-day on Sunday. No one knows exactly how many people there were inside when the fire broke out," Alexandre Eremeyev, an official with the local Russian emergency services ministry, said in a statement.
"Where to look for people? How many are there? That has greatly complicated the work of the firefighters," he said, adding that the thick smoke was also hindering their task.
Some 300 firefighters and rescue personnel were rushed to the scene and the fire was brought under control around 17:30 (GMT), local emergency officials said.
Russia's minister of emergency services, Vladimir Puchkov has gone to Kemerovo, RIA Novosti said.
Austrian Chancellor Sebastian Kurz offered his sympathies.
"My condolences to the families and friends of the victims of the terrible fire in the shopping mall in Kemerovo. It is tragic that so many children are dead or missing. I wish a speedy recovery to those injured," he said on Twitter.
It is the deadliest blaze in Russia in recent years.
A shopping mall fire in March 2015 killed 11 people in Kazan, the capital of Tatarstan some 800km east of Moscow.
In April 2013, a fire ravaged a psychiatric hospital in the Moscow region, killing 38 people, most of them patients who were engulfed by flames as they slept behind barred windows.
Just months later, in September 2013, 37 people were killed when a fire swept through a psychiatric hospital in the village of Luka in northwest Russia.
In 2009, 156 were killed in a nightclub fire in the city of Perm, 1 200km east of Moscow in one of the deadliest accidents in Russia's modern history.