At least 64 people were killed after a fire tore through a shopping center in Russia Sunday night.

Local firefighters said they had extinguished the blaze by Monday morning, which ripped through the Winter Cherry Mall in the city of Kemerovo in Siberia, nearly 2,000 miles east of Moscow.

Russia’s Investigative Committee confirmed Monday that the death toll from the fire had risen to 64, including dozens of children.

Eleven people are still missing, as firefighters search the burned out shopping center for survivors. A movie theater inside the mall collapsed, authorities said, raising the possibility that some of the missing remain trapped beneath the rubble.

No information has been released regarding the cause of the fire, but Russian authorities detained four people for questioning.

According to a report by the Ekho Moskvy radio station, witnesses said that the shopping center’s fire alarm system failed to activate during the blaze, and mall staff did not alert shoppers or organize the evacuation of the shopping center.

At least one emergency exit was jammed, The Telegraph reported, and several people trapped inside the mall were seen jumping from windows to escape the blaze.