Two 17-year-olds have been arrested on suspicion of murder after an 18-year-old man became the latest victim of London's knife crime epidemic.
Police are appealing for witnesses after the death took the total number of murders in the capital since the turn of the year above 50.
The Met said officers on patrol were flagged down by the driver of an oncoming car at around 8pm on Wednesday who told them there had been an altercation nearby.
An off-duty paramedic gave what help they could until the London Ambulance and the Air Ambulance arrived, but the young man, who was named by his father as Israel Ogunsola, was pronounced dead at the scene.
Chief Superintendent Sue Williams, leading Hackney borough, said: "My officers were flagged down to the Link Street incident and did all they could to try to save the life of the teenager, rendering emergency first aid and chest compressions with the help of an off-duty paramedic until the ambulance service and London's Air Ambulance arrived.
"They are devastated they were unable to prevent yet another tragic death in the capital."
She added: "In Hackney we are working hard to prevent further violence and keep people safe - we have extra officers on the streets, both highly visible and in plain clothes carrying out a range of intelligence-led operations and patrols."
Speaking at the scene on Thursday morning, Labour's shadow home secretary Diane Abbott called for an anti-knife crime strategy in London similar to that of Glasgow.
"It's really tragic, it's really horrible and mothers all over the capital must be thinking 'I can say goodbye to my son this morning but will he come back tonight?'
"Whether their son will turn out to be a victim or a perpetrator, it's traumatising for families."
She blamed the wave of bloodshed on London's streets on cuts to policing and youth and social services.
"Here in Hackney we've lost one in 10 of our police officers since 2010, but there also needs to be more work done in youth work, in schools, even in mental health," she said.
Citing Glasgow, which has dramatically cut its murder rate by taking a coordinated public health approach to knife crime, she said: "They have brought the number of deaths from knife crime down to zero last year."
She said the Borough of Hackney was down to one police station as a result of cuts.
"It makes it harder for people to report crime but it gives a sense in the community that we are not guarded."
She added that London Mayor Sadiq Khan had no choice but to close police stations because of Government cuts to policing.
When asked about Met Commissioner Cressida Dick's recent comments about social media fuelling knife crime as young people use it to goad their rivals, she replied: "I think social media is a symptom not a cause."
She continued: "I think we have to look at the cuts in youth services, the cuts in policing and the fact that many young people leaving school don't have jobs to go to for the real underlying causes."
Ms Abbott added that the drugs trade was "just one aspect" of knife crime in London.
"I think we have to remember that not all of this is gang related at all, a lot of it is just people who have quite trivial arguments with each other and choose to solve it with a knife attack and that's very frightening," she said.
Elsewhere in Hackney just hours earlier a man in his 50s died outside a bookmakers in Upper Clapton Road following a suspected fight, the Met said.
Stabbings in England and Wales are at their highest levels since 2010/11 and the escalating violence has been especially acute in London, with 13 people killed within two weeks last month.
On Tuesday, 16-year-old Amaan Shakoor became the youngest murder victim in London so far this year after he was fatally shot on Monday in Walthamstow.
His death came after that of Tanesha Melbourne, 17, who was gunned down around 30 minutes earlier just three miles away in Tottenham.
Both were apparently casualties of gang violence.
Scotland Yard said it is currently investigating 55 suspected murders since the start of 2018, including the deaths of two children whose bodies were found in Sussex.
