A residential flat with six floors has collapsed with people inside in Tassia estate, Embakasi Ward, Embakasi East Constituency.
The number of people trapped inside is yet to be known, but rescue operations are underway.
At least 17 people have been rescued so far and taken for medical attention at nearby hospitals by first responders from City Hall and the Kenya Red Cross Society.
Public Works Principal Secretary Gordon Kihalangwa, who was among government officials who visited the scene, said the ill-fated block had 46 residential houses.
The landlord, Mama Kanyoni who was expected to avail tenancy records, was missing from the scene after the building collapsed.