Two boys have been shot minutes apart from each other in Harrow, northwest London.
Police were called just minutes apart, at 1.17pm, to the shootings at two locations in close proximity in High Street, Wealdstone.
A 15-year-old boy was found with a gunshot wound.
Two minutes later at a different but nearby location, a 13-year-old boy was also treated for gunshot wounds.
Police are investigating to determine whether the two incidents are linked.
No arrests have been made and no firearm has been recovered, police said.
A grey Adidas sweatshirt with blood stains on the hood lay crumpled on the ground outside a Specsavers store along with a police exhibit number.
A shopkeeper said the youngster was “lucky to be alive” and they believe a bullet grazed the back of his head.
The manager of a betting shop, who did not give his name, said he was passing by on his lunch break and saw people gathered outside Specsavers around a black man on the ground.
He said: “He was holding his head down. I could not see his face but could see his white t-shirt was proper covered in blood.
“He was sitting calmly as the paramedics were looking after him.”
He described Wealdstone as a “kind of rough area and it can be a bit aggressive”.
He added that “seeing police around here is just another day” and he was used to seeing boys “just hanging around” in the street.
A green first aid bag could be seen behind the cordon as forensics officers took photographs and passers-by were diverted from the scene.
Both the boys are in hospital and neither is believed to have suffered life-threatening injuries.
The shootings come amid growing concerns about knife and gun crime and youth violence in the capital.
There have been 64 suspected murders in the capital this year, prompting fears that violent crime could rise to the highest levels for a decade.