A teenage girl has been shot dead, police said.
The victim - believed to be aged around 15-years-old - was gunned down inside a building in Hackney, east London.
Police were called to the scene at Eastway, near Hackney Wick station, shortly before 4pm today.
Three males were arrested nearby and taken to an east London police station, where they remain in custody.
A Metropolitan Police spokesman said: "Officers believe they know the identity of the deceased and have begun informing family, however they await formal identification.
" A post-mortem examination will be held in due course."
The London Ambulance Service and London's Air Ambulance attended but the girl was pronounced dead at the scene.
Detectives from the Met's Homicide and Major Crime Command are investigating.
Anyone with information is asked to call Crimestoppers on 0800 555 111.
A police spokesman said the males who were arrested are all under 18.