At least 12 people were killed and 21 injured, five seriously, Sunday when a building collapsed in Cameroon's business hub Douala, firefighters and local authorities said.

The four-storey block collapsed onto another residential building around 1:00 am (0000 GMT) in the north of the city, a senior fire brigade official told AFP on condition of anonymity.

Charles Elie Zang Zang, a Douala municipal councilor, added rescue services were searching through the rubble for survivors.

Douala's Laquintinie hospital stated it had taken in 13 patients and said two -- a girl of three and a young woman of 19 -- had died.

It added three other children among those injured were receiving emergency pediatric treatment.

Five people died in similar circumstances in Douala in 2016 when authorities blamed poor state of repairs and apparent violations of building regulations.

In June that year, local authorities identified 500 buildings in danger of collapse.