A cyclist was attacked from behind and suffered a broken eye socket.
The attack happened at around 8.40pm last Friday (May 5).
The victim, a 36-year-old man from York, was riding his bike down Wains Road in Dringhouses.
He narrowly avoided a collision with a child, aged around six-years-old, who was also riding a bike.
The cyclist spoke to the child and then took his bike off the road and pushed it through a nearby gate, when he became aware of a man behind him.
Punched and assaulted
The cyclist was then punched him in the back of the head and knocked to the floor, where he was assaulted and sustained a broken eye socket. He required surgery for his injuries.
It is believed the offender is aged between 19 and 25-years-old and was with two women at the time of the assault.
Police are requesting anyone who witnessed the assault, or anyone who has information which could assist the investigation to contact them.