Russia’s Emergency Situations Ministry said on Monday that at least 64 people had been killed in a fire in a shopping mall in the Siberian city of Kemerovo.
As many as 41 children may be among the victims, and 16 people are missing, Russian officials say.
The blaze started on an upper floor of the Winter Cherry complex while many of the victims were at the cinema.
Video posted on social media showed people jumping from windows to escape the flames on Sunday.
Some 660 emergency personnel have been deployed in the rescue effort.
The cause of the blaze is not yet known but authorities have launched an investigation.
Kemerovo, a key coal-producing area, lies about 3,600km (2,200 miles) east of Moscow.
As well as a multiplex cinema, the shopping centre, opened in 2013, includes restaurants, a sauna, a bowling alley and a petting zoo.
The fire is believed to have started at around 17:00 (10:00 GMT) in a part of the building that contains the entertainment complex, local media report.
"According to preliminary information, the roof collapsed in two cinemas," Russia's Investigative Committee said in a statement.
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Yevgeny Dedyukhin, deputy head of the Kemerovo region emergency department, said the area of the fire was about 1,500 sq m.
"The shopping centre is a very complex construction," he said. "There are a lot of combustible materials."