A teenager was killed and another man left injured after they were gunned down in a street by two men wearing bandanas.
Terrified witnesses described how three gunshots were fired in Hindrey Road, Clapton, east London, at 8.20pm on Saturday.
A 19-year-old man was rushed to hospital but later died, while a 22-year-old man was understood to be in a stable condition, Scotland Yard said.
The pair were sat in a car at the time of the shootings, witnesses said.
Zach Carpenter, 18, saw two men wearing bandanas across their faces enter Hindrey Road before he heard three loud bangs.
One of the men was black with a red and white chequered bandana, while the other man was white and was wearing a black bandana, he said.
Mr Carpenter said: "I was walking home from the shop when I saw a black man and a white man walking down the main road and turn into Hindrey Road. After about 30 seconds I heard three loud bangs. It's unnerved me a bit because my family live nearby."
The Aberystwyth University student, whose family has lived in the area since he was 10 months old, said there were known feuds between gangs on rival estates.
"It's not so much a war, more of a feud between the Pembury and Nightingale estates, and another one," he said.
Detectives from Operation Trident, which investigates gang-related crime, are hunting two suspects seen running from the scene. One is black, police said, while the second is light-skinned, possibly of Asian or Turkish appearance.