The United States and United Nations separately condemned Tuesday's attack on the Dusit Hotel complex.
A State Department spokesman called it "a senseless act of violence," while UN Secretary-General Antonio Guterres denounced what he termed a "horrible terrorist attack."
The US embassy in Nairobi is offering to assist Kenyan authorities in responding to the attack.
UN, US condemn Tuesday attack on Dusit Hotel complex in Nairobi.
A US State Department spokesman condemned the attack and said "all Mission personnel are safe and accounted for."
The US Embassy is closely monitoring the incident and is working with Kenyan authorities to determine if there are any American citizens affected, the spokesman said.
"We condemn this senseless act of violence," the spokesman said. "The U.S. Embassy has actively offered assistance to local authorities."
Meanwhile, UN Secretary-General Antonio Guterres is condemning “the horrible terrorist act.”