At least 41 people have been killed in a bus crash near the Kenyan town of Narok, west of the capital Nairobi, the Red Cross says.
"It is a horrible scene. Bodies are strewn all over," said police traffic officer Samuel Kimaru.
The bus, travelling from Nairobi to Homa Bay on Lake Victoria, reportedly plunged into a valley and rolled over several times, ripping off its roof.
The BBC's Abdullahi Abdi says road accidents are common in Kenya.
He says many drivers speed, while main roads lack safety features such as crash barriers and reflective signs for night-time drivers.
A similar number of people were killed when another bus overturned in February.
The latest crash reportedly happened at about 0200 local time (2300 GMT on Wednesday).
Mr Kimaru said four of the dead were children.
"It is difficult to tell exactly what happened but all indications point to speeding and possibly overloading," the AFP news agency quotes him as saying.
"We are having a difficult time recovering the bodies because this place is hilly and bushy."
Kenya recently launched a traffic safety campaign to try to reduce the numbers who die on the country's roads every year.
Magistrates were to start travelling along highways inside trucks to administer on-the-spot fines to offending motorists, such as minibus drivers who have not installed seat belts.
More than 2,000 people have died on Kenya's roads so far this year.