We are awaiting an update on the condition of those injured," cops said.
A man with a sword was arrested in Hainault, east of London, after several people were attacked and injured, the Metropolitan Police said on Tuesday.
The force said it was called just before 7:00 am (0600 GMT) after a vehicle drove into a house and reports that "people have been stabbed".
"At this time we understand the suspect went on to attack other members of the public and two police officers," a statement read.
"We are awaiting an update on the condition of those injured."
London Ambulance Service said its teams treated five people and took them all to hospital. There was no immediate word on their condition.
.The Met, which polices an area of 620 square miles (1,605 square kilometres) of Greater London, said a 36-year-old man was arrested at the scene.
Deputy Assistant Commissioner Ade Adelekan said: "This incident does not appear to be terror-related."
Video footage and photographs posted on social media appeared to show a man on the streets near houses with what looked to be a Samurai-type sword.
Emergency service vehicles, including police, fire and ambulances, were seen behind cordons, including near the town's Underground station.
London Mayor Sadiq Khan said he was "absolutely devastated" at hearing of the incident and was in close contact with the Met Police commissioner.
"The police offices and emergency services showed the best of our city -- running towards danger to protect others and I thank them from the bottom of my heart," he said.
Last week, Conservative Prime Minister Rishi Sunak criticised the Labour mayor's record on knife crime in the British capital.
According to official statistics, knife crime increased in London by 20 percent in 2023, with 14,577 offences -- one percent lower than pre-pandemic levels in the year to March 2020.
In England and Wales as a whole, there was a seven-percent increase in knife crime to 49,489 offences, with most (29 percent) in metropolitan areas, the Official for National Statistics said.
