A teenager is in a "serious" condition in hospital after he was shot in the back in the street in the early hours.
Police said they were called at 12.35am on Sunday morning to an incident in Westbourne Park, west London.
They found a 16-year-old boy at the junction of St Luke's Road and Tavistock Crescent, suffering from a gunshot wound.
Scotland Yard said officers from the Trident shootings team, which investigates gun crime in the black community, were appealing for help from anyone who may have seen or heard anything suspicious or anyone who may have information concerning the incident.
Anyone with information is asked to call the Trident team on 020 8785 8580 or Crimestoppers on 0800 555111 to remain anonymous.