A tour bus rammed head-on into a truck, killing six people and injuring more than 40 others in northeastern Thailand, local media reported on Friday.

The accident took place at around 1 a.m. local time (1700 GMT Thursday). The double-decker bus with some 60 passengers aboard was on its way back to Bangkok from northeastern Thailand's province Roi Et.

The bus veered off in heavy rains and crashed into a truck travelling in the opposite direction.

Both drivers were dead along with four passengers sitting at the front of the bus, the Daily News reported. Forty others were injured and eight seriously.

Police said that the bus driver might have fallen asleep.

The crash was still under investigation.