A man has been stabbed to death in front of passers-by in a London street.
Witnesses said they saw the victim lying on the pavement with a neck wound as members of the public tried to save his life.
Cristina Serrao, who was passing in her car shortly after the attack, told The Independent she saw a woman was trying to stop the man bleeding.
“I saw a black male on floor with a woman holding blue roll of tissue to his neck, he was laid on his back quite near the road,” she added, saying a white van also pulled up to help.
“There were no crowds or anyone else nearby – I initially thought maybe he had been knocked down by the van until I saw her holding his neck.
“By the time the lights changed, police vans and cars were rushing down Hampstead Road and some went down side roads.”
The Metropolitan Police said officers were called to the scene in Camden at around 11.45am and have closed roads in the area.
A spokesperson said the attack happened in Granby Terrace, at the junction with Hampstead Road, adding: “Officers attended, along with the London Ambulance Service and a London Air Ambulance vehicle.
“The man was pronounced dead at the scene.”
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Members of the public were evacuated from the scene as medics treated the victim on the pavement, with road closures put in place and some train services disrupted.
Surrounding roads were cordoned off and the victim’s body was covered in blue tarpaulin.
The busy intersection sits between Euston railway station and Mornington Crescent Tube, near the Ampthill estate.
Investigators are working to identify the victim, who is thought to be aged in his late teens or early 20s, and inform his family.
A spokesperson for Scotland Yard said a 17-year-old boy has been arrested in connection with the investigation and was taken to hospital.
Enquiries continue to establish the full circumstances of the attack.
There have been several murders in recent weeks, including a shootings in Newham and Enfield and deadly stabbings in Islington, Manor Park, Brixton, Eltham, Peckham and Croydon, with the victims as young as 15.