A 14-year-old boy was killed and four other people were injured after a stabbing in London on Tuesday involving a man with a sword.
Police said the incident was not believed to be terrorism-related and there was no ongoing threat to the wider community.
Officers tasered and arrested the man after the attack near Hainault in east London. Video footage showed a man wielding what appeared to be a sword.
"It is with great sadness that I confirm one of those injured, a 14-year-old boy, has died. He was taken to hospital after being stabbed and sadly died shortly afterwards," London's Metropolitan Police Chief Supt Stuart Bell said.
He said it was not believed to be a targeted attack.
Metropolitan Police Assistant Commissioner Louisa Rolfe told reporters a 36-year-old man had been arrested on suspicion of murder and was currently in hospital, having suffered injuries when his van collided with a building.
Two members of the public and two police officers were in hospital with non-life-threatening injuries. The two police officers had stab wounds requiring surgery.
The UK's King Charles paid tribute to those affected and praised the courage of the emergencies services that helped to contain the incident.
"His thoughts and prayers are with all those affected - in particular, the family of the young victim who has lost his life," a Buckingham Palace spokesperson said.
