Police have launched a murder investigation following the fatal stabbing of a teenager in southeast London.
Emergency services were called to Miall Walk in Sydenham, near Crystal Palace, at 9.30pm on Friday.
The 19-year-old died at the scene despite first aid efforts, the Metropolitan Police said. London Ambulance Service paramedics also attended.
Police said the teenager's family have been told of his death but formal identification and a post-mortem examination will take place in the coming days.
Detective Chief Inspector Chris Wood said: "Met officers have been working through the night to commence what will be a rigorous investigation into the death of this young man.
"Police cordons remain at the location as a painstaking forensic examination gets under way.
"The victim's mother has been to the scene and has met with officers.
"She and other family members will be provided with ongoing support, and my heart goes out to her as she faces up to the first day of the rest of her life without her son.
"I can assure her, and indeed all Londoners, of my total commitment to finding the person or persons responsible for this murder and bringing them to justice.
"The support of the local community, and of anyone who may know anything about this tragic incident, will also be crucial. If you have any information, please get in touch."
Murder detectives from the Met's Specialist Crime Command are leading the investigation. No arrests have yet been made.
Posting on Twitter, Lewisham West and Penge MP Ellie Reeves offered her condolences to the man's family.
"Incredibly saddened to hear of the fatal stabbing of a 19 year old boy on Miall Walk in Sydenham last night," she wrote.
"My thoughts & deepest sympathies are with the victim's family. Yet another senseless loss of life, another family devastated by knife crime and it needs to stop."