Police have launched a murder investigation after a man, believed to be in his thirties, was found with critical injuries outside Queensbury Tube station near Edgware.
He died at the scene almost an hour after officers were called to Cumberland Road just after 9pm on Tuesday.
Another man, in his 20s, took himself to a north London hospital at about 9.10pm suffering from a gunshot wound.
He remains in a stable condition, Scotland Yard said.
The older man’s death brings the total number of people to have been killed in violence in London since the start of the year to 59, Sky News analysis has found.
A police cordon has been put up on Cumberland Road and Essolado Way, where detectives believe the attacks took place.
Officers are at the scene and are examining CCTV footage of the area.
A ballistic examination is also under way as part of the forensic analysis.
One shopkeeper said they heard gunshots at about 9pm.
Detective Inspector Justin Howick said: “I would like to appeal to anyone with information to contact police at the earliest opportunity.
“Detectives are busy at the scene and working to build a clear picture of the circumstances of this fatal attack.”
Nobody has been arrested and police are still informing the victim’s next-of-kin.
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Formal identification and a post-mortem will take place in due course, police said.
Anyone with information should call police on 101 quoting CAD 7757/01May, or contact Crimestoppers anonymously on 0800 555 111.