The commissioner of the Met Police said the force has “not lost control” of London’s streets despite a “ghastly” spate of violent crime.
Cressida Dick said her officers are doing “everything they can” to reduce street crime but they need support from the public for justice to be served.
Six people have been killed in the capital in the last seven days.
Ms Dick said 300 extra officers will be on duty across the weekend in the worst affected areas.
Her comments came after a 30-year-old man was arrested in Hackney over the murder of Tanesha Melbourne-Blake, 17, who was shot dead in Tottenham on Monday.
The teenager was killed in a drive-by attack as she was with friends.
The rising wave of violent crime meant the number of suspected murders in London in March was higher than that of New York.
It emerged on Thursday that the Met has opened 55 murder investigations in London this year and there were nine non-fatal stabbings from Thursday night into Friday morning in the capital.
Ms Dick said she she does not believe the recent spike in attacks is due to cuts to police budgets, adding that arrests have already been made in the five murder investigations that have been launched since Monday.
“It is important that we investigate those to the best of our ability and that we bring people to justice. I anticipate that we will. We are very good at that,” she said.
Six deaths in a week
- Devoy Stapleton, 20, was stabbed in Ellerton Road, Wandsworth, on Easter Sunday
- Tanesha Melbourne-Blake, 17, died the next day, on 2 April, after a drive-by shooting in Tottenham
- Just 30 minutes later Amaan Shakoor, 16, was shot in the face in Walthamstow. He died later in hospital
- Henry Vincent, 37, was stabbed at a house in Lewisham on 4 April. He also died later in hospital
- A 53-year-old man collapsed on 4 April after reports of an altercation in Clapton, north-east London. He was pronounced dead at the scene and no arrests have been made
- Israel Ogunsola, 18, was stabbed to death in Hackney on 4 April. Two 17-year-olds have been arrested on suspicion of murder
Ms Dick admitted the Met is “stretched” and has asked City of London officers to help with the current demand in murder detectives.
“This is not an unprecedented time, but it is a very worrying time,” she said.
Speaking at Stoke Newington Police Station in north London, she added: “Over the last year I have visited countless and met with countless, I am afraid, I am sorry to say, family members of people who have lost their lives.”
She said the force “almost always” brings people to justice and anticipated there to be charges in connection with the recent spate of attacks.
Just 30 minutes after Tanesha was killed, 16-year-old Amaan Shakoor was shot in Walthamstow and died in hospital the following day.
Officers said they are keeping an open mind about the attack, and at this stage there has been no suggestion that the two killings are linked.
On Friday afternoon a Section 60 order, granting police stop and search powers across the Borough of Newham, was announced in response to the stabbing of a 13-year-old boy in Gainsborough Avenue on Thursday.
The order will remain in place until 06:00 on Saturday.