A boy who was shot dead in a park in west London has been named as 15-year-old Rene Graham.
Emergency services were called to Emslie Horniman’s Pleasance Park in Ladbroke Grove at about 19:20 BST on Sunday.
Local residents have said a pre-carnival event involving children was taking place at the time.
Four men, two aged 21 and the others aged 20 and 25, have been arrested on suspicion of murder and remain in custody.
There were “no reports of any other injuries” the Met Police said.
Det Ch Supt Christina Jessah said: “I understand that the public, especially those who live and work in the area, will be shocked and concerned by this incident.
“All of us at the Met share that concern and we are using all of the resources at our disposal to identify those involved.”
Local residents have said there is “shock, disbelief and fear” in the neighbourhood, especially among parents, some of whom have said they will be taking “extra precautions” as a result.
Cristina Cortinas, 40, who lives in the area, told BBC London that the shooting was a “tragedy” and “really sad for the community”.
“A young boy has lost his life,” she said.
“I have got two small, young children – I fear for them, I fear for their future, I fear for them living in this community.
“We are very much a tight community and we are all very sad.”
‘Understandably worried’
Elizabeth Campbell, the Conservative leader of the Royal Borough of Kensington and Chelsea, said she could not “begin to imagine what family and friends are going through”.
“Many people will be understandably worried about this terribly violent incident happening in our neighbourhood,” she added.
“I’m glad to hear from our police teams that there will be a very visible police presence in the coming days.”
The council said the park, Emslie Horniman’s Pleasance, was likely to remain closed throughout today.
About 20 officers have been stationed around the crime scene and the forensics team continues to carry out investigations.
‘Violence must stop’
Joe Powell, MP for Kensington and Bayswater, described the shooting as “horrific news”.
He posted on X: “My thoughts are with his family. These senseless acts of violence must stop.”
The Mayor of London Sadiq Khan said: “I am heartbroken by the devastating news that a 15-year-old has needlessly lost his life in Ladbroke Grove.
“I remain in regular contact with the Met Police who are working round the clock to investigate this horrific incident.”
The Met said residents can expect to see a “significant police presence” in the area to provide “reassurance and support”.
Fatal shootings in London are far less common than stabbings, although there have been six homicides involving guns so far this year, and three of those have been recorded in the last six weeks.
Last month, the Met said that “lethal barrel discharge”, where a weapon is fired, was at its lowest level in 15 years.
But a number of high profile cases, including a shooting in Dalston in May, which left a nine-year-old girl fighting for her life, have caused huge public concern.
The young age of the victim of this latest shooting, believed to be just 15 years old, and the reports that he was attacked as a pre-carnival event for children took place nearby, will also raise worries about the safety of young people as schools break up for summer.
The Metropolitan Police previously said six men had been arrested but this figure was later corrected to four arrests.