Motorists plying Thika Road have been advised to use alternative routes after an oil tanker overturned and spilled fuel on the road at the Roysambu area.
Kenya National Highways Authority (KeNHA) said the incident has affected outbound traffic.
"Police are on site and controlling traffic, as well as ensuring the safe evacuation of the tanker.
"Motorists and members of the public are asked to evacuate from the area and to cooperate with the authorities as the evacuation process takes place," KeNHA said in a statement.
A fire engine from the Kenya Army has been deployed to the scene.
