An 11-year-old boy driving a pickup truck crashed into a group of Buddhist monks on a pilgrimage in northeastern Thailand, killing eight and injuring 14 others.

The 35 monks had begun a 260-kilometer walk from Mukdahan province to Ubon Ratchathani when the accident occurred.

Authorities said the truck appeared to swerve before leaving the road and striking the monks, with the cause of the crash still under investigation.

Security footage captured the vehicle hitting the monks as they walked in a single file along the roadside, CBS News has reported.

The boy is in police custody and will be questioned in the presence of child protection officials.