MOSCOW — The number of people killed in an apartment building in central Russia that partly collapsed after an explosion rose to 38 on Thursday, as hope dwindled that the few people who remain missing would be found.

Rescue work at the site was interrupted for long periods because of fears that more walls would crumble, long after the explosion at 6 a.m. on Monday in the city of Magnitogorsk caught many residents asleep in their beds.

Three people remain unaccounted for, and only one ambulance was standing by on Wednesday, according to local news reports, signaling the diminished chances of pulling more residents from the pancaked rubble of some 25 apartments in the freezing cold.

The apartment complex was home to around 1,300 people before the explosion, which left a gaping hole in the extensive facade. But the Emergencies Ministry declared that most of the building remained fit for habitation.