Horrified residents have described seeing armed police swarm their block of flats moments before officers shot dead a man who had a gun and was threatening to kill someone.
Police were called to an address in Cedar Road, Enfield, north London, at 11.50pm on Sunday.
They shot a white man outside a flat on the sixth floor of Picardy House, an 11-storey former local authority building near Lavender Hill cemetery.
Scotland Yard said the 43-year-old, who has not yet been identified, was pronounced dead at the scene and a non-police firearm was recovered.
A Metropolitan Police spokesman said: "No arrests have been made. There are no other reported injuries.
"The Met's Directorate of Professional Standards (DPS) are in attendance at the scene.
"As a matter of routine, the incident has been referred to the Independent Police Complaints Commission (IPCC) for investigation."
Neighbours desbcribed seeing around 20 armed officers enter the building before hearing two shots that "sounded like firecrackers".
Residents said the shooting happened outside a flat on the sixth floor, which has been sealed off by police.
Dowan Mustafa, 20, who lives on the seventh floor with his mother, said he saw armed police officers swarm the building, and later heard two shots being fired.
He said: "I was looking over our balcony and I saw coppers swarming the building. They were armed - around 20 of them.
"The coppers came in and after I heard the shots.
"I heard two gunshots, proper loud gunshots, which woke everyone up.
"They are saying it was a shotgun but we are not too sure.
"Everyone has been evacuated from the sixth floor."