Police have launched a murder investigation after a man was stabbed in east London - as patrols are increased across the capital following a number of stabbing and shooting deaths in recent days.
Scotland Yard said "specialist units" were undertaking "high-visibility patrols".
There are also "operational tactics in targeted locations to prevent further violence and to provide reassurance to the communities in those areas", said deputy assistant commissioner Matthew Twist.
The "coverage of the Violent Crime Task Force in targeted areas across London" is also being stepped up, he added.
In the early hours of Monday, a man, in his 40s, was stabbed to death in Stratford, east London.
An 18-year-old man was fatally stabbed in Wandsworth on Friday afternoon. Shortly afterwards, Eniola Aluko, 19, was shot dead in Plumstead.
Mr Aluko, from Thamesmead, died of a gunshot wound to the neck and chest, according to a port-mortem examination.
On Saturday, a man in his 30s was stabbed to death in Tower Hamlets.
Two people have been charged with murder after the Wandsworth attack.
A 17-year-old boy, who cannot be named for legal reasons, and Mohammed Nadir Dafallah, 18, are due to appear at Wimbledon Magistrates' Court on Monday.
Four others, aged between 16 and 19, have been released under investigation, and police made another arrest - a 20-year-old man - on Monday.
Five arrests have been made in connection with the attack on Mr Aluko.
There have been no arrests as yet following the Tower Hamlets or Stratford incidents.
Since news of the deaths emerged, London Mayor Sadiq Khan has again been attacked by US President Donald Trump.
Mr Trump described Mr Khan as a "disaster" and a "national disgrace", tweeting: "LONDON needs a new mayor ASAP. Khan is a disaster - will only get worse!"
He later added: "He [Mr Khan] is a national disgrace who is destroying the City of London!"
A spokesman for Mr Khan said the mayor would not "waste his time responding to this sort of tweet" as he is "focusing on supporting London's communities and over-stretched emergency services".
Mr Twist said: "We have increased the coverage of the Violent Crime Task Force in targeted areas across London this weekend and officers from across the boroughs, supported by colleagues from specialist units, will continue to undertake high-visibility patrols which will remain in place today and into the start of the week.
"We have been using a number of operational tactics in targeted locations, to prevent further violence and to provide reassurance to the communities in those areas."
Anyone with information is urged to call the Metropolitan Police direct, or to contact Crimestoppers on 0800 555 111.