A black man is recovering in hospital after being stabbed in an unprovoked attack by a gang of white youths.
The assault happened in Hampstead, north London, on Saturday night, Scotland Yard said.
The 46-year-old man was walking along Fleet Road when he was set upon by a group of four or five teenagers.
He was attacked, stabbed in the chest and racially abused, police said. He is in a stable condition in hospital. Police are appealing for information.
Det Sgt Joe Lumley said: "This is an unprovoked assault. It is essential we trace those responsible quickly, and we urgently need the public's assistance."
After stabbing him, the gang fled towards Lawn Road.
They are described as being aged about 18, and two of them were wearing grey Nike hooded tops.