Six people, five of them teenagers, have been hospitalised following five separate knife attacks in London on Thursday.
A 13-year-old boy was one of the victims, suffering serious wounds after being stabbed in east London.
Three youths have been arrested on suspicion of grievous bodily harm in connection with that attack, Newham police said.
The boy, who was reported to be in a serious but stable condition, was attacked in Gainsborough Avenue in Newham shortly before 7pm on Thursday.
Earlier, a man was arrested on suspicion of attempted murder after three boys were taken to hospital following a stabbing attack in Mile End, east London. Two 15-year-old boys remain in a serious but stable condition.
Another youth, aged 16, who was treated for minor injuries, has been arrested on suspicion of conspiracy to commit grievous bodily harm, Tower Hamlets police said.
At about 7pm, a male in his late teens was taken to hospital in west London following a stabbing in Ealing Broadway. Police said they were awaiting an update on the victim’s condition.
The first incident of the evening happened at about 5.30pm when a 15-year-old boy was stabbed in East India Docks. The victim was in a stable condition on Thursday night and his injuries were not considered to be life-threatening.
A fifth attack occurred in Herne Hill in south London when a man, believed to be in his 40s, was stabbed just after 10pm. He was taken to hospital and police were awaiting an update on his condition late on Thursday.
No arrests have been made in connection with the Ealing Broadway, East India Docks or Herne Hill attacks.
Bedfordshire police said on Thursday night that two men had been shot in Luton. Both were taken to hospital but neither was thought to have suffered life-threatening injuries.
The London incidents came as protesters and community leaders gathered in east London to call for an end to a recent spate of violence in which several teenagers have died, pushing London’s murder toll for the year past 50.
Crowds gathered near Hackney Central station, close to where Israel Ogunsola, 18, was stabbed to death on Wednesday.
Ogunsola’s murder followed that of 16-year-old Amaan Shakoor two days earlier. He was shot in Markhouse Road, Walthamstow, minutes after the shooting of 17-year-old Tanesha Melbourne in Tottenham the same evening.
Protest organisers from the Guiding a New Generation group – commonly known as GANG – led gatherers into a wide circle where they locked fists and were invited to share thoughts about the recent violence over a megaphone.
One speaker, who addressed the crowd under the name Scripture, said he had seen people being killed at close hand.
“It’s not a pretty sight,” he said. “You know what, it’s not a computer game. You’re not gonna come back, bruv. These youths who are doing damage to each other are not coming back and they’re not learning their lesson neither.”
Pauline Pearce, the Hackney mayoral candidate for the Liberal Democrats, Pauline Pearce told the rally that the recent string of stabbings and shootings were partly a result of young people feeling “disenfranchised” by their environments.
She said: “A lot of the children feel disenfranchised; they don’t feel they belong, they haven’t really got a meaning. They don’t feel that they have that connection to society, so a lot of things go wrong for them and sadly this is the sort of retaliation that comes.”
Pearce, who works as a community activist, called for the current mayor of Hackney to lobby the mayor of London, Sadiq Khan, to “do the right thing” and reduce crime in the capital.