At least 17 people have been injured after a Nyamira Express company bus rolled into a valley at Amabuko near Keroka Town along the Kisii-Keroka highway.
Keroka Traffic Base Commander Iltabul Kochale said the incident occurred at around 6pm Wednesday.
The bus, which was coming from Nairobi, was headed to Sirare in Migori County.
The injured passengers were taken to Masaba Sub-County Hospital and later referred to the Kisii Teaching and Referral Hospital.
"The bus had just dropped some passengers at Keroka Township and had about 25 left inside at the time of the accident," said Mr Kochale.
The Traffic boss cautioned locals against congesting crash scenes saying this hampers rescue efforts.
"A good number of people who rush to accidents scenes are also interested in looting," he added.
Kisii Governor James Ongwae visited the scene of the crash.