Police shot a man in the early hours of Thursday after unsuccessfully trying to subdue him with a Taser stun gun.
Metropolitan police said in a statement that officers were called to a disturbance at address in Claremont Road near Brent Cross, in northwest London, at 2:45am.
The man was believed to be in possession of a knife, police said.
After fleeing the scene, the man was shot with a Taser gun, "but with no apparent effect", before being shot using a regular bullet by firearms officers.
The man was taken to a hospital in central London and there are no other reported injuries.
A spokesman for the Independent Police Complaints Commission told BuzzFeed News that it had launched an investigation into the incident.
Investigators are at the scene and the post-incident procedure has begun.
The directorate of professional standards was also informed, the police said.
Patrick Smith is a senior reporter for BuzzFeed News and is based in London.
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