Moscow. March 26 (RHC-agencies) -- At least 64 people were killed by a fire which engulfed a busy shopping mall in the Siberian city of Kemerovo, Russian investigators said on Monday, and some of the dead were children.

The fire, one of the deadliest in Russia in the last century swept through the upper floors of the “Winter Cherry” shopping center on Sunday afternoon which housed a cinema that was packed with parents and children at the time of the blaze. It quickly spread throughout the complex. Witnesses say that fire alarms did not work.

Emergency services said they had extinguished the blaze, but later said it had reignited, and that rescuers were struggling to reach the building’s upper floors because the roof had collapsed. Earlier on Monday, people had posted appeals on social media seeking news of their relatives or friends, and authorities set up a center in a school near the mall to deal with inquiries.

Anna Kuznetsova, Russia’s children’s rights commissioner, said the fire had been caused by incompetence and warned there were many similar shopping centers.

State investigators, who have opened a criminal investigation into the blaze, said four people had been detained over the fire, including the owners and lessees of outlets inside the mall. 

The Interfax news agency cited an unnamed local official source as saying the main theory being looked at was that the fire had been caused by an electrical short circuit.