Police have urged a man who helped the teenage victim of a "vicious" sectarian assault to come forward.
The 15-year-old boy was assaulted in the Rossdowney Road area of Derry by up to four teenagers at about 22:10 BST on Saturday.
He was taken to hospital after being kicked in the head and punched in the face.
Officers are keen to trace a man who stopped his car and drove the teenager home.
"This was a vicious attack, which is being treated as a sectarian assault at this time," PSNI Inspector William Calderwood said.
Appeal for witnesses
He said the boy was walking along Rossdowney Road with friends when they were stopped by a group of approximately 30 youths.
"One of the males in the group, described as being at least 5ft 6ins tall with brown hair and a blonde fringe, aged 16 or 17 and wearing glasses, stopped and spoke to the boy.
"It was reported this male then called over three other youths who were with him and the 15-year-old boy was assaulted", he added.
Insp Calderwood said asked anyone who witnessed the assault to come forward.
He especially appealed for the driver of a white jeep who took the boy home to contact police.