Rescue efforts to find further survivors of a building collapse in Nigeria that killed at least 34 people were called off late Wednesday, emergency officials said.

The National Emergency Management Agency said 13 were rescued following the collapse of a five-storey building in commercial capital Lagos on Tuesday. Workers and their families had been living at the building site in Lekki, one of the city’s most upmarket neighborhoods.

“Operations have been concluded with 34 dead and 13 rescued alive after reaching ground zero,” Ibrahim Farinloye, a spokesman for the emergency agency, told Anadolu Agency.

“Investigation on the cause of the collapse has started by various federal and state agencies.”

Local government officials said the building did not conform to the approved building plan and have summoned the contractors for questioning.

“Based on preliminary reports and investigation, it was discovered that the collapsed building was served a contravention notice for exceeding the approved floors and thereafter sealed by the Lagos State Building Control Agency,” Lagos Information Commissioner Steve Ayorinde said in a statement late Wednesday.

He added that “in a brazen act of defiance and impunity” the building’s owners had “criminally unsealed the property and continued building beyond the approved floors.”

The state government has ordered inspections on other construction projects involving Lekki Worldwide Estate Limited.

Construction site accidents are a common occurrence in Nigeria, mainly due to substandard building materials and poor official oversight.

Last year, four people, including three children, were killed in a building collapse in Lagos.

•Photo shows rescue workers before at the collapsed Lekki building before the process was called off late Wednesday.