Death toll from Nigeria's building collapse has risen to 20, an official said on Friday.

Axar.az reports citing Anadolu Agency.

A total of 45 injured were being treated at various health facilities in the Nigerian commercial capital Lagos, the city’s Health Commissioner Jide Idris said.

On Wednesday, a building containing a school in Lagos city caved in and the National Emergency Management Agency had put the death toll at eight on Thursday.

Building collapse is not uncommon in Nigeria owing to what officials called substandard materials and non-adherence to regulations.

Lagos government said on Thursday it would commence immediate demolition of houses without official approval. The collapsed building was known to have been marked for demolition until the incident.

At least 115 persons -- including 84 foreigners -- died in a similar building collapse in 2014 at a popular church in Lagos.