Fifteen people died and 70 were injured when fire swept through a market and nearby homes in central Nairobi in the early hours of Thursday.
The blaze broke out in a timber yard, said Nairobi regional coordinator Kangethe Thuku, a senior official.
It started at around 2:30 a.m. and spread through Gikomba market and nearby apartments and shanties before being contained around 90 minutes later, according to Emergency Service St John Ambulance.
Located in the densely crowded downtown part of the city, Gikomba is the heartbeat of a huge informal market, selling everything from second-hand clothes to hardware. It has been damaged several times by fire.
Thuku said the death toll from Thursday's blaze had reached 15.
"About five... arrived dead in the hospital but we still have about nine bodies in the burning buildings because we want to confirm and ensure the safety of those buildings," he said.
Some victims were taken to Kenyatta National Hospital (KNH) whilst a 15th fatality was at Mama Lucy Hospital.
A further 70 people were injured in the fire, whose cause had yet to be established, he said
A Reuters photographer saw bodies being brought out from a building and people sifting through ashen wreckage as smoke rose from the site.
The acting Chief Executive of KNH said the hospital was on alert for more victims. "In case we have any more, we are ready for them," said Thomas Mutie.