One man has been killed and two injured in a knife fight that broke out at Westfield shopping centre in Stratford, east London.
Police swooped on the ground floor of the giant shopping mall after reports of a brawl.
All victims are believed to be in their early 20s. One was pronounced dead at the scene by paramedics. He has not been formally identified.
The two injured men were taken to hospital. The fight is believed to have involved several men.
A spokesman for the Metropolitan Police said: "We were called to Westfield shopping centre after reports of a large fight. One man has been arrested but this is not necessarily in connection with the stabbing."
The London Ambulance Service sent two crews and an air ambulance.
"Despite extensive efforts to resuscitate him, the patient was pronounced dead at the scene.
"Two male patients were treated at the scene, one of them for stab wounds and a second for minor injuries, and both have been taken to hospital.
"We were also called to Stratford underground station and sent two further ambulance crews and another responder in a car."