Police are investigating after two men died in separate, allegedly targeted, homicides in Melbourne's outer suburbs. 

Officers responded to reports of a man being shot outside a property on Gentles Avenue, Campbellfield, in the city's north, about 10:10pm on Friday. 

The 60-year-old from Craigieburn was taken to hospital where he later died. 

Two men are under police guard in hospital following the man's death.

Detectives believe the fatal shooting was targeted. 

Detectives are also investigating whether the discovery of a burnt-out car on Northbourne Road in Campbellfield just after 11pm is linked to the incident.

At this stage it is believed the incident was targeted and the people involved are known to one another, police said.

Police are also investigating a separate fatality on Friday evening in Kurunjang in Melbourne's west.

It is alleged a brawl broke out between a group of 30 to 40 people on McBurnie Drive shortly after 7pm. 

When police arrived they found three people who were injured. Despite the efforts of emergency services, an 18-year-old Kurunjang man died at the scene.

A 15-year-old and 22-year-old from Harkness were taken to hospital with non-life-threatening injures and are under police guard.

Police believe the incident was targeted and are appealing for witnesses to contact Crime Stoppers.

"We do believe that they are separate incidents and we have people that police are hoping to speak to in hospital," Acting Superintendent Kelly Walker said on Saturday. 

Police said the 18-year-old was fatally injured with an "edged weapon". 

Acting Superintendent Walker said the community could be reassured police were investigating all avenues of enquiry to apprehend those responsible.