At least 102 people were killed after a fire broke out on Monday near a fuel depot at an industrial area on the outskirts of Nairobi, Kenyan media reported.
A Capital FM radio reporter at the scene said more bodies were being recovered, while scores of injured people were rushed to hospital, DPA reported.
Rescuers were responding, but emergency vehicles were having trouble reaching the scene, with fears the fire would spread to a nearby slum.
Witnesses told the radio that a pipeline that passes through the Sinai slum burst earlier in the morning. Some residents may have been siphoning fuel at the time of the explosion.
Sinai is part of a belt of slums collectively called Mukuru that run along the length of Nairobi's industrial area, about 10 kilometres outside the city. More than half a million people a cramped together in crowded conditions in the area.