A public service vehicle (PSV) bus, which was ferrying passengers, has overturned near GSU Headquarters along Thika road.
According to eyewitnesses who were at the scene, the bus driver was trying to avoid hitting a private car when the crash occurred.
Following the incident, several people sustained injuries with no casualty so far reported.
Some passengers with injuries were pulled out of the wreckage of the bus by a mob that had gathered moments after the crash.
The emergency response team visited the scene swiftly and rushed the injured to hospital for treatment. The exact number of those injured in the accident has not been confirmed.
Photos captured at the scene showed an overturned bus on the highway while first responders attempted to remove passengers stuck inside the vehicle.
A heavy snarl-up formed affecting the traffic flow as residents and motorists gathered to take a look. The police are yet to issue an official statement regarding the accident.