Amid freezing temperatures, firefighters put out the blaze just before dawn and pulled six bodies from under the debris, said Alexander Kulichenkov, a spokesman for the regional division of the Emergency Situations Ministry. The fire occurred on the site of a sporting complex that is under construction.
Three people were injured and one hospitalized, Kulichenkov said; the dead all appeared to be construction workers, reports AP.
The blaze appeared to have started when scaffolding caught fire, he said.
Russia records about 18,000 fire deaths a year roughly 10 times the rate in the United States. Experts say fire fatalities have soared since the collapse of the Soviet Union because of lax enforcement of safety standards.
Russian small missile ships - the Grad Sviyazhsk and the Great Ustyug - set off for a mission to the Mediterranean Sea