The blaze broke out on Wednesday in a first-storey cafe before the building collapsed, trapping 25 people under the rubble, according to local media reports.
Emergency workers continued to clear away debris on Friday in Kazan, the capital of Russia’s Tatarstan region about 500 miles (800 kilometres)east of Moscow.
Tatarstan President Rustam Minnikhanov said managers had failed to comply with fire safety regulations.
“Such tragedies do not happen without the guilty,” he was quoted by Interfax as saying. “It is a great tragedy … we do not know how many more people will be among dead.”
Investigators have detained the shopping centre’s 30-year-old director and are looking into a wide range of theories, including arson, the news agency reported.
Igor Panshin, head of the regional emergencies ministry previously said that as many as 25 people may have been killed when the shopping centre collapsed.
“There may be up to 25 people under the rubble of the burnt-out shopping centre in Kazan. No one among them is alive,” Panshin told Interfax on Thursday.
One rescue worker died whilst trying to save people trapped beneath the collapsed building, RIA news agency reported.
According to the regional emergencies ministry, foreign citizens from Azerbaijan, Uzbekistan, Vietnam, Kyrgyzstan and Tajikistan have been injured. (Reuters)