A 17-year-old boy has been stabbed to death in north-east London.
No arrests have been made over the teenager's killing in Walthamstow on Sunday night, the Metropolitan Police said, after the latest in a series of such attacks in the capital.
Officers were called to the High Street just after 11.30pm and found the male suffering from a serious stab injury.
The boy was taken by London Ambulance Service to an east London hospital in a critical condition and died in hospital a short while later.
A murder investigation has been launched and officers from the homicide and major crime command have been informed.
A crime scene remains in place, police said.
The boy's next of kin have been told.
Anyone with information is asked to contact police on 101 or call Crimestoppers, anonymously, on 0800 555 111.
The death was the second fatal stabbing in London over the weekend and follows a string of knife attacks in the capital in recent weeks.
A 23-year-old man died from a stab wound after being found unconscious by police in Uxbridge, west London, in the early hours of Saturday.
Officers were sent to the scene in Waterloo Road after a call from London Ambulance Service.
The victim, from Hayes, west London, was taken to a hospital in west London but died shortly after.
Police have launched a murder investigation and urged witnesses to come forward. No arrests have been made.
Meanwhile on Friday a man in his 30s was fatally stabbed following an incident at a barber shop in Harlesden, north west London.
The deaths come after a fortnight of rampant knife crime in the capital, which saw 10 other victims suffer from fatal or serious stab wounds.
On Wednesday the Metropolitan Police launched the latest phase in its campaign to crack down on knife crime.