A 21-year-old man may have been involved in a brawl shortly before being fatally injured after he was knocked down by a passing taxi.

Police in York received reports of a "violent disorder" involving a group of men near the Nuffield Hospital in Haxby Road at 1.48am this morning.

A few minutes later, as officers were en route, a taxi driver called 999 to say his silver Volvo S80 saloon had been in a collision with a pedestrian nearby.

Paramedics, firefighters and police officers battled to save the seriously injured man but he died at the scene. Next of kin have been informed.

Four men from the York aged 22, 20, 18 and 18, have been arrested in connection with the violent disorder. Two women, aged 20 and 16, were also arrested on suspicion of assisting an offender.

The taxi driver, a 58-year-old man from York, is helping police with enquiries.

A 20-year-old man, believed to have been involved in the violent disorder, was taken to York District Hospital for treatment to a serious hand injury. He is also assisting police with enquiries.

Detective Inspector Andrea Kell, of York CID, said: “This is clearly a very tragic incident and we are supporting the young man’s family while the police investigation continues.

“I urge anyone with information that could assist our enquiries to get in touch without delay.”

The stretch of road remained closed while police enquiries are ongoing and local diversions are in place.

Detectives have also issued an urgent appeal to locate a potential key witness.

The man they are urging to come forward is believed to have witnessed the violent incident and collision after being dropped off by at taxi on Haxby Road at about 1.45am. It is understood he had got caught the taxi from Duncombe Place in York at about 1.30am.

He spoke with an Irish accent and officers think he could have important information to assist the investigation.

If this is you or you know who he is, please contact North Yorkshire Police immediately on 101, select option 2, and ask for York CID, extension 2453. Or email YorkCID@northyorkshire.pnn.police.uk

Witnesses to the violent incident are urged to contact North Yorkshire Police on 101, select option 2, and ask for York CID. Or email YorkCID@northyorkshire.pnn.police.uk Alternatively, call 101, option 1, and pass details to the Force Control Room quoting “Operation Hydrus”.

Anyone who witnessed the collision should call 101, select option 2, and ask for Peter Wood. Or email Peter.Wood@northyorkshire.pnn.police.uk If you would prefer to remain anonymous, please pass information to Crimestoppers on 0800 555 111 quoting reference number 12140175183.