BEIJING -- Beijing police have detained 18 people in relation to the fire in an apartment that killed 19 people on Saturday.

A fire broke out Saturday night at a three-story apartment at Xinjian village of Daxing district, a southern suburb of the city. A total of 19 people died. Eight people were taken to hospital.

Detainees include seven people who managed the apartment block, seven electricity workers, and four construction workers at a refrigeration facility, where the blaze is thought to have started. None of the 11 workers holds qualifications as required by the authority, police said.

Preliminary investigation showed there was a refrigeration facility in the basement of the apartment where the fire might have started.

Police are investigating other suspects.

Beijing has ordered a 40-day city-wide safety check following the fire.