Two people died after a seven-story building under construction collapsed in Nigeria’s commercial capital Lagos in the early hours of Sunday and rescue efforts were underway to find survivors, Lagos State Emergency Management Agency said.

The building was being constructed next to a hospital in the neighborhood of Oniru, said the agency’s chief executive Olufemi Oke-Osanyintolu, adding that at least four people were still trapped under the rubble.

Reuters witnesses saw large earth-moving equipment removing debris as a crowd watched.

Building collapses are frequent in Africa’s most populous country, where regulations are poorly enforced and construction materials often substandard.