A supervisor in charge of the ill-fated Kasarani building twice disregarded warnings from authorities to stop its construction on Tuesday, it has now emerged.
Two women who were helping with the building's construction told the Nation that they noticed cracks on the ground floor walls on Tuesday morning.
Another construction worker who spoke to the Nation said City Hall officers arrived at the site on Tuesday morning for inspection.
The officers are said to have advised workers to leave the construction site immediately.
However, the building's supervisor reportedly asked the workers to ignore the warning and proceed with construction.
Witnesses also said officers from the National Construction Authority also attempted to stop the construction on Tuesday morning but were chased away.
Rescue efforts for victims officially began on Tuesday evening, coming hours after a seven-storey building that was under construction collapsed in Kasarani, Nairobi.
The number of people trapped under the rubble is still unclear, but locals at the site said around eight or nine people were near the building when it came down on Tuesday.
Several people, mostly construction workers, are feared trapped in the rubble.
Rescue workers could be seen Tuesday night as they tried to locate the victims. Excavators are also on site to help with moving heavy concrete.
Those injured have been taken to St Francis Hospital in Kasarani.
Ronald Karauri, the MP for Kasarani, arrived on site following news of the building collapse.