A total of 20 apartments have been engulfed by a fire caused by a gas explosion in a town in the Moscow region, local emergency officials said Monday. The household gas exploded in a five-storey apartment building in Bronnitsy town, leaving three people injured, the authorities said, adding those people have already been hospitalized. The explosion first caused fire in six apartments and swiftly spread to other apartments. Firefighters and rescuers have been evacuating residents from the building. According to rescuers, some people could remain under the rubble when a section of the building collapsed due to the explosion.