Two boys were attacked by a group of teenagers in a sidestreet of County Road in Walton.
A male on a bike threw something at the boys on County Road yesterday afternoon, and then followed them into Newark Street.
He then attacked one of the boys, and then a group of teenagers joined in the assault.
Two girls tried to defend the victims.
A 15-year-old boy suffered injuries to his arm, while the second boy was not seriously hurt.
The incident happened at around 4.35pm yesterday afternoon.
A police spokesman said to the ECHO : "We are appealing for witnesses following an assault in Walton yesterday, Monday, 8 July.
"It was reported that at around 4.35pm, two boys were walking along County Road when a male passing on a bike threw something at them.
"The male then followed the boys into Newark Street where he assaulted one of them, before a number of youths, described as white and around 14-16 years old, joined in and assaulted the victim.
"It is believed two female youths tried to stop the assault. One of the male offenders was described as wearing a blue hoody and black pants.
"The 15-year-old victim sustained a non-life threatening wound to his arm. The second boy was left uninjured and the offenders made off in the direction of Stuart Road.
"An investigation is underway and house-to-house and CCTV enquiries are being carried out in the local area."
Detective Inspector Paul Speight said: “I would appeal to anyone who was in the area around County Road or Newark Street and saw the assault or a group of youths making off from the scene to please get in touch.
“This was a nasty assault involving a number of people and we are sure that someone must know the identity of the offenders. If you were involved, or have heard any information after the incident, please contact us and let us know. Any information could prove vital to the investigation.”
Anyone with information is asked to DM @MerPolCC, call 101 quoting ref. 19100365456 or contact Crimestoppers anonymously on 0800 555 111.
