At least 40 people have been killed after a bus travelling from the Kenyan capital Nairobi to Kisumu, in the west, veered off the road, police say.
Many reportedly died at the scene of the accident and police fear the death toll may rise with the possibility of passengers trapped in the wreckage.
“The roof of the bus was ripped off,” an official said.
Police said the driver had lost control and plunged down a slope at a notorious accident black spot.
Local radio station Midnimo tweeted an image of an overturned vehicle that looked severely damaged.
Radio Midnimo Kenya@RMidnimo42 DIE after bus travelling from Nairobi to Kisumu crashes at Fort Ternan on Londiani-Muhuroni Road, Kericho County Police Commander James Mogera says.
Children are believed to be among the dead.
Highway roads in Kenya can be notoriously dangerous.
Last December, some 36 people died in a head-on collision between a lorry and a Nairobi-bound bus on a road near Migaa in Kenya.