A Metropolitan Police spokesman said the teenager died at about 11.10pm.
Police said there was no clear motive for the shootings yet and no-one has been arrested.
At this very early stage we must retain an open mind regarding the circumstances of the incident and any motive.
Detectives from Trident are leading the inquiry and an incident room will open in the morning.
Witnesses to the shooting or anyone with information about the incident are asked to call police on 101 or Crimestoppers on 0800 555 111.
More top news
A man who owns and works in an antique store was shocked to find out he wasn't the only person in the building late at night.
A former model has been found guilty of murder after shooting her millionaire ex-boyfriend in his Costa del Sol home.
Some warm sunshine today, but also scattered heavy showers in the South-west.