The bus going from capital Nairobi to western town of Kakamega had 52 on board when it overturned.

Fifty people have been killed in a bus accident in western Kenya early on Wednesday, authorities said.

Witnesses and police on Wednesday said the bus swerved off the road while driving down a steep slope, and rolled into a ditch at 4 am local time (0100 GMT) in western Kericho county.

According to police, the bus was travelling from Nairobi to the western town of Kakamega and was carrying 52 passengers.

Rift Valley regional police boss Francis Munyambu told the Associated Press that survivors from the bus were receiving treatment at local hospitals.

The Kenyan Red Cross wrote on Twitter that the bus had overturned. However, more details on the cause of the accident were not immediately available.

Official statistics show that around 3,000 people die annually in road accidents in Kenya, but the World Health Organization estimates the figure could be as high as 12,000.

In December 2017, 36 people died in a head-on collision between a bus and a truck in the east African country.

In 2016, more than 40 people died when an out-of-control fuel tanker rammed into vehicles and then exploded on a busy stretch of highway.