The police have declared DusitD2 hotel and the area around 14 Riverside Drive a no-go zone for members of the public, including politicians.
In a statement, the National Police Service said the area is an active crime scene.
About six armed militants raided the hotel on Tuesday leaving several dead. The police are yet to give an official toll of deaths.
"Until it is declared safe, everyone not actively involved in the operation should avoid the area," the police said.
The operation to evacuate those holed up in the hotel and building continued until Wednesday dawn.
About 45 people, who were stuck at the complex, were safely evacuated at about 3.45am.
Sounds of gunfire continued to be heard in the morning, pointing to fears the attackers could still be in the premises.
Inspector General of Police Joseph Boinnet, in an earlier statement, said it is a suspected terror attack.
Several people with gunshot and soft tissue wounds were rushed to nearby hospitals.
A number of Kenyans offered to donate blood to the injured.
