Senior sergeant Gary Barber said a group of people who'd left a party on Kay Rd became involved in a dispute with another group, on Tripoli Rd.
During the fight, a vehicle arrived and its occupants fired a gun, understood to be a shot gun.
Two people were arrested for being drunk and disorderly, and interfering with police as they tried to close the situation down.
The arrests were unrelated to the shooting.
Barber said it was not clear what caused the fight, but it was a confused melee that the Criminal Investigation Branch (CIB) was trying to get to the bottom of it.
He said at this stage, there was no suggestion gangs were involved.