BBC/Paul MurphyA 13-year-old girl has been stabbed and six teenagers arrested on suspicion of attempted murder.
Humberside Police said she was found at the side of the A63 in Hessle at about 07:00 GMT.
She suffered “lacerations” to her neck, chest and abdomen and her injuries are “life-threatening”, the force said.
Four boys aged 14, 15, 16 and 17, and two girls aged 14 and 15 were arrested soon after in a wooded area nearby.
Det Sup Simon Vickers said he believed the attackers “knew the victim”, who is in a critical condition in hospital.
“I understand this incident will rightly cause concerns amongst the community and I would like to offer my assurances that as a part of our initial investigation we have six individuals in custody who are all being questioned by detectives,” he said.
“At this time, we do believe the attackers knew the victim and inquiries are ongoing to establish the circumstances around the incident.”
A cordon is in place around the wooded area off Ferriby High Road and there will be a police presence over the weekend, he added.