The fire broke out Saturday night at the three-story apartment at Xinjian Village of Daxing District at the southern suburb of the city.
Among the victims, eight were under 18 years old, He Rui, deputy chief of Daxing District, said at a press briefing late last night.
Eight persons were taken to a hospital. Seven of them are out of danger and one remains in a critical condition, state- run Xinhua news agency quoted Rui as saying.
Preliminary investigation showed there was a 5,000- square-meter refrigeration facility under construction at the basement of the apartment. Fire-fighters suspect the fire might have started there.
More From This Section
More than 400 people lived in the apartment block and all have been relocated, He said.
The district government has set up medical, legal and family teams to deal with affairs arising from the deadly fire. They contacted 95 family members of the victims.
Police are investigating other suspects.
Beijing has ordered a 40-day city-wide safety check. Local officials are urged to check every village and every courtyard for safety risk.