Police arrested three people following an alleged assault in Airport West last night.
The incident occurred on a tram at the intersection of Matthews Avenue and Dromana Avenue just after 10pm.
A 28-year-old Melbourne man was on the tram, when it is alleged he was assaulted by four people, in what police described was an unprovoked assault.
He was taken to hospital with serious injuries.
Two teenage girls aged 16 from Werribee and 14 from Hoppers Crossing, were arrested nearby, along with an 18-year-old Roxborough Park man.
The trio have all been released and are expected to be charged on summons with affray, attempted robbery and assault related offences.
A second male left the scene and remains outstanding however police have been able to identify the man and the investigation is ongoing.
Anyone who witnessed the incident is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential crime report at www.crimestoppersvic.com.au