Detectives investigating an armed street brawl in north London believe it may be linked to the area's lucrative trade in heroin.

A murder investigation has begun following the fight between two gangs of Turkish and Kurdish origin, in Finsbury Park on Saturday.

Witnesses reported seeing up to 40 men fighting with knives, baseball bats and firearms in Portland Gardens, near Green Lanes.

Police arrived at the scene at 1815 BST to find three men with gunshot wounds, one of whom later died from his injuries.

It was not a racially-motivated attack with one gang against the other - we believe it is like a turf war

Suzanne Nuri, London Turkish Gazette

Detectives are investigating the possibility that it was a fight between rival groups of drug dealers.

Chief Superintendent Stephan James told BBC London: "Green Lanes is renowned as being the centre for certain parts of the drugs trade, particularly heroin.

"This may be a dispute relating to that and I am going to ask the Serious Crime Group to explore that and explore it thoroughly."

Suzanne Nuri, from the London Turkish Gazette, told BBC London: "We believe that the problem has been going on for the past 18 months to two years and I think this is a culmination of all of that.

"It was not a racially-motivated attack with one gang against the other - we believe it is like a turf war."

Green Lanes, which was cordoned off while it was examined by forensic experts, has been re-opened.