Three men are being held on suspicion of attempted murder after a man was seriously injured in Feltham, south-west London.
Police were called to an "altercation" in Lancing Road just after 3.45pm on Wednesday.
A man, 20, had suffered serious injuries, which the Met said were "possibly as a result of the use of a weapon".
He was taken to hospital by London's Air Ambulance. His condition is non-life threatening or changing.
Police arrested three men who were being held at a police station in west London.
Anyone with information about the incident is asked to call 101, quoting 5189 of August 28, or Crimestoppers anonymously on 0800 555 111.
