A 17-year-old girl has been stabbed to death at a park in east London.
Police were called to St Neots Road in Harold Hill, Romford, at about 21:30 GMT on Friday.
The girl was pronounced dead at the scene.
The Metropolitan Police has begun a murder investigation, although no arrests have been made. The girl’s next-of-kin have been informed, and a post-mortem examination is due to be held.
It comes less than a week after 20-year-old Ché Morrison was stabbed to death outside Ilford train station in east London.
Police have sealed off the park and forensic officers are at the scene.
One resident, whose flat overlooks the park, said she rushed out after her family heard a commotion and tried to help the girl as she lay bleeding.
A small group of people cried and hugged each other after laying a bunch of flowers at the cordon with the message “we love you forever in our hearts.”
Another message attached to a floral tribute said: “You are so strong. We will always remember you.”
Hairdresser Ellie Best, 17, said she and her family had moved to Harold Hill from east London for the “good strong community”.
She said: “No-one should have to get a call to say that their child has been killed.
“It is becoming more and more like central London here. Children did not fight or anything and you did not hear of people being mugged. There has never been knife crime here before – it is just in the last six or seven months.
“I worry for the younger youths. Police need to talk to them about the dangers of carrying knives because the message is not getting through.”
Miss Best said the park was used by local children to “just hang out”.
One woman told the BBC the stabbing highlighted “one of the issues we have in Havering – community are not reporting what they’re seeing, therefore Havering is not seen as an area of concern”.
Friday’s stab victim is the first teenage girl to die in a homicide in the capital this year.
She became the 18th person to be killed in London this year, and the fifth teenager to die.
Last year, two 17-year-old girls and one 18-year-old woman were murdered in London.
Acting Det Ch Supt John Ross, of the Met, described the latest death as a “tragedy” and said police would carry out extra patrols around Harold Hill “in the coming days”.
He also said there had been a reduction in knife crime since the middle of last year, particularly in relation to people aged under 25.
“But we are not complacent, bearing down on violent crime in the streets of London is a top priority for the Met,” he said.
Urging potential witnesses to come forward, he added: “Your information could take a knife off the street or save a life.”
London Mayor Sadiq Khan said he was “devastated” by the stabbing.
Mr Khan, who has a 17-year-old daughter himself, urged members of the community to contact police.
Councillor Paul McGeary, who represents the Gooshays ward where the killing happened, arrived with fellow councillor Tele Lawal to lay flowers at the scene.
A small group of people cried and hugged each other after laying a bunch of flowers at the cordon with the message, “we love you forever in our hearts”.
The park is known locally as Amy’s Park, with a playground in the centre, which has been the focus of forensics investigations.
Both councillors said they and their families had used the park, which is in a residential area.
Mr McGeary spoke of his “shock and horror” that it had happened in the semi-rural outer London borough.
He said: “This is not something that happens here and I am just completely surprised.”
He could not say if it was gang-related, but described it as “tragic”.
He added: “It is very shocking for the whole community. I think people will be talking to each other and hopefully providing support to the relatives of the unfortunate person who died.”
Ms Lawal, 22, said: “It is not an area where you will frequently see violence like this.
“It is going to shock our community but it just shows the strain that is happening with young people, with our police and the resources we need in our community to tackle violence like this.”
A resident who lives opposite the park, who did not know the victim, described her death as “a terrible thing”.
He said: “She was just 17 and just starting her life. How could anyone do that to a woman? It is disgusting. It is happening a lot in London lately. It is becoming a normal thing and that is terrifying.”
MP for Hornchurch and Upminster in Havering Julia Lopez described the attack as “utterly senseless”.