An 18-year-old has been stabbed to death at a store on a busy London shopping thoroughfare, crowded with Boxing Day bargain hunters.
The south London teenager was killed at the Foot Locker store on Oxford Street as hundreds of thousands of people shopped nearby on the opening day of post-Christmas sales.
Police said they were called about 1.45pm on Monday to reports of a stabbing.
London Air Ambulance and London Ambulance Service also attended but the man was pronounced dead at the scene.
The officer in charge of the case said there had been a confrontation between two groups of youngsters and confirmed that "a number of people" had been arrested.
The BBC has reported that 10 people have been arrested.
Detective Chief Inspector Mark Dunne said officers were looking to speak to as many witnesses as possible.
Police had seized a number of weapons, but no guns, and it was not certain whether the murder weapon was among those recovered, he said.
A forensics team erected a white tent in front of Foot Locker, overlooked by Christmas lights.
Confused Boxing Day bargain hunters and tourists were coming up to the police cordon to take pictures and ask officers what had happened.