"According to preliminary information, the fire broke out in a boiler room located on the roof. Fire crews are on site," Gladkov said on Telegram late on Friday night.
Meanwhile, city Mayor Valentin Demidov said on Telegram that all residents of the multi-story apartment building have been evacuated.
"Firefighters and rescuers are checking the apartments on the upper floors," Demidov said.
In a later update, the mayor said that the fire was eliminated and that its likely cause was a violation of safety rules during repair work. None of the apartments were damaged by the blaze, according to preliminary information.
Local emergency authorities told Sputnik that nobody was killed or injured in the fire. The affected residents have been offered temporary accommodation at a hotel.