Two people have been killed and at least 14 others injured in an "abhorrent" spate of separate stabbings across London this weekend.
Since Friday night police have dealt with stabbings in Coulsdon, Streatham, Chislehurst, Pimlico and Harrow.
Separate murder investigations were launched in Croydon and Kilburn after two 22-year-olds were stabbed to death just 24 hours apart.
Extra police officers have been deployed across capital, the Met said.
London's weekend of violence began on Friday night in Croydon when one 22-year-old man was stabbed to death inside a block of flats on Wisbeach Road, Thornton Heath.
The victim has not yet been named by police who said another male was taken to hospital after being injured in the same attack.
Det Supt Nicky Arrowsmith described the latest surge in knife crime as "needless and completely abhorrent."
On Saturday night Sven Badzak, also 22, was fatally injured after he and a friend fled a group of males in Kilburn.
Mr Badzak was taken to hospital where he later died, Det Ch Insp Darren Jones said.
He added: "At this early stage we believe Sven and his friend became involved in an altercation with a group of males.
"As this group chased the pair, Sven and his friend became separated. Sven fell to the ground and was attacked by a number of the group.
"His friend was also attacked but managed to seek sanctuary in a shop. However, he remains critically ill in hospital."
There have been no arrests in either murder investigation.
Elsewhere in London, police dealt with stabbings in other parts of Croydon as well as Streatham, Chislehurst, Coulsdon and Pimlico.
All attacks are unconnected and there have been arrests in only two of the Croydon stabbings.
A 20-year-old man who was stabbed in Hindes Road, Harrow, on Sunday afternoon remains in a life-threatening condition, the Met Police said.
All the other victims did not have serious injuries, detectives have said. Source: BBC