Late Tuesday, Cabinet Secretary for Interior and Coordination of National Government Fred Matiang'i said security teams have evacuated scores of Kenyans and other nationalities from the buildings after a nine-hour operation.

"We are now in the final stages of mopping up the area and securing evidence and documenting the consequences of this unfortunate event," he told journalists.

"I can now report that the country is now secure and that the nation remains calm, that Kenyans and all our visitors are now safe," he added.

The DusitD2 complex, which houses several multi-national offices and a hotel, is located in the leafy Riverside area of Westlands, Nairobi.