The accident occurred late Sunday when the bus was travelling from the town of Meru to the coastal city of Mombasa.

The bus plunged off a bridge about 40 metres (130 feet) into the Nithi River valley below.

Pictures published in local media showed the bus ripped apart after rolling down the steep slope, with reports saying wreckage and bodies were strewn in the water and on the riverbank.

The National Transport and Safety Authority (NTSA) said in a statement on Twitter that 33 people had died and that it had halted the operations of the bus company involved, Modern Coast Express Ltd.

“A thorough multi-agency investigation into the crash and an evaluation of the operator’s safety operational standards is currently under way,” it added.

County commissioner Norbert Komora had told reporters earlier: “The search is still on and we are trying to retrieve the wreckage.

“Investigations are still going on to establish the cause of the accident”.

The number of people killed on Kenya’s roads has increased in recent years.

In the first half of 2022, 1,912 people were killed, up nine percent from 1,754 in the same period last year, according to NTSA figures.