A 15-year-old boy has died and three teenagers have been arrested after a fatal stabbing outside a London community centre.
The Metropolitan Police said they were called to the centre in Romford on Saturday night after fighting broke out as youngsters left a birthday party.
The boy was found with knife wounds and died at the scene.
Three male teenagers have been arrested on suspicion of murder and have been taken for questioning.
Police were first called to the community centre on Clockhouse Lane at 21:05 BST.
There had been reports of fighting between groups and the centre being damaged.
Det Sgt Gurj Singh said: “Response officers who attended the initial calls were confronted with up to 100 youths leaving a birthday party gathering at a community centre.”
Romford MP Andrew Rosindell said it was “devastating” that a young life had “so tragically been cut short on our streets tonight”.
The boy’s next of kin have been informed, although his identity has not yet been released.
A bus driver in his 50s was treated for a head injury at the scene, the Met said, adding that there were no other injuries.
Police have appealed for witnesses.