Four police officers were injured, including three thought to have been stabbed, in an incident today.
The four were taken to hospital after they were attacked by a man in Kingsbury Road, Kingsbury, north west London, Scotland Yard said. Their conditions were not immediately known.
A man was arrested, a spokesman said.
The Yard spokesman said: "Police were called at approximately 8.40 this morning to a disturbance in Kingsbury Road, Kingsbury.
"Officers attended and attempted to speak with a man, who subsequently attacked them.
"Four officers were injured during the incident and have been taken to hospital.
"A man has been arrested on suspicion of attempted murder and remains in custody at a north London police station."
Three of the officers are thought to have been stabbed while the other suffered a hand injury, it is not clear how.
Olympia Logofagul, 24, who works at the Kings Coffee shop on Kingsbury Road, said: "I was working and I saw some police officers standing outside.
"There were a lot of officers, more than five but no more than 10."
A spokeswoman for London Ambulance Service said they took five patients to hospital, all conscious and breathing.
She said: "We were called at 8.50 this morning to an incident in Kingsbury Road.
"We sent two single responders in cars, four ambulance crews and a duty officer.
"We treated five patients, they were all conscious and breathing, and they were taken to hospital."