An 11-year-old boy has crashed a pick-up truck into a group of monks on a pilgrimage walk in northeastern Thailand, killing eight.

A total of 35 monks from Mukdahan province, about 600km northeast of the capital Bangkok, were on the pilgrimage. It’s reported that they were only 30 minutes into the 260km walk to Ubon Ratchathani province when the vehicle ploughed into them.

Five monks were killed at the site on Thursday while three others died in hospital, according to Mukdahan governor Worrayan Boonnarat.

Fourteen others were hospitalised with four still in a critical condition.

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Police said the boy was in custody.

They said the cause of the accident was still under investigation, but they were told by the monks that they saw the vehicle losing balance before it slid off the road and crashed into the group.

NBC reported that security camera footage from a local rescue group showed the monks walking single-file on the roadside before they were struck by the vehicle.