Of the injured, 21 are receiving treatment at the Kenyatta National Hospital, 160 at Mama Lucy Kibaki Hospital, 19 at Mbagathi Hospital, 14 at Modern Komarock Hospital, and eight at Nairobi West Hospital.
"One lorry of an unknown registration number that was loaded with gas exploded, igniting a huge ball of fire that spread widely," Mr Mwaura said.
"A flying gas cylinder hit Oriental Godown, burning down the said godown which deals with garments and textiles," he added.
The residents first reported hearing a big explosion followed by a huge ball of fire that engulfed the area. Several explosions and the fireball sent the residents into panic.
The inferno also damaged several vehicles and commercial properties, including small and medium-sized businesses, the government spokesman said.
"The scene has now been secured and a command centre is now in place to help coordinate rescue operations and other intervention efforts," he said.
Multiple explosions
With rescue operations still ongoing, the government said the scene has now been secured but warned members of the public to keep off the cordoned area.
Eyewitness and frightened area residents said their peaceful night was disrupted by multiple explosions that sent flames and smoke billowing into the sky.
"Huge explosions, huge fireballs, people screaming and running everywhere for fear of more explosions. Power cut, some people driving out of the estate. We can hear sirens now. The fire is in a warehouse next to an estate called Skyline and an informal settlement called Mradi," an eyewitness told Nation.Africa.
"We are all out of the houses. The explosions are huge, the sky is red. No firefighters. It's scary so people are forwarding whatever gives hope," said a Nation journalist who lives in Nyayo estate.
The raging fire engulfed buildings, with residents of neighbouring estates coming out in droves amidst screams for fear of being caught in the inferno.
*Story updated with latests figures on death toll and injuries.
