A 55-year-old man has died after being shot in inner Melbourne.

It's understood the man was getting out of a car and was shot in the back on the intersection of Napier and Gertrude streets in Fitzroy about 4.15pm on Tuesday.

Police believe the man was involved in an altercation with a number of people at a vehicle parked on Brunswick Street before being fatally shot.

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Passersby found the man and called triple zero.

Ambulance crews treated the man, who is yet to be formally identified, but he died at the scene.

Police have cordoned off the area and a crime scene has been established

Detectives are still working to determine the exact circumstances of the incident.

Police said it appeared to be a targeted incident, with the parties involved possibly known to each other.

More to come.