At least 29 people have died in a bus that plunged off one of Thailand’s highest bridges.

The accident occurred around midnight on Friday in Lom Sak district, Phetchabun province, as the bus with 40 passengers headed for the northern province of Chiang Rai.

Several passengers were critically injured.

The local police commander said the bus was apparently driving fast before the crash and it was suspected that the driver fell asleep at the wheel.

The bus was carrying 40 passengers and several were critically injured.

Transport Minister Chadchart Sitthipunt said the bus smashed through the safety barrier of the Phamuang bridge which links north and northeast Thailand.