A stray lion that escaped from Nairobi National Park injured an elderly man on Friday.
The lion was sighted in the morning near City Cabanas on Mombasa Road.
A video posted to social media showed the black-maned lion running along the highway as motorists hoot and shout.
The Kenya Wildlife Service (KWS) said it had sent three units to capture the lion and the operation was still under way.
The KWS also said the man injured by the lion had been taken to hospital.
This is the fourth time in less than a month that lions and lionesses have strayed out of the park, causing panic.
(READ: Stray lions spark wild jokes)
In the first incident, when three lionesses strayed, the KWS said the big cats were protecting their cubs by moving them out of the entire pride at the park.
Two days later, a man reported to the Lang'ata Police Station that two lions had mauled his three goats.
On Wednesday night, another flock was killed by lions near Lang’ata.