Two police officers and another man are being treated in hospital after an incident at a block of flats in north London.
The Metropolitan Police said it was called at around 7.20pm to Noel Park Road in Wood Green after residents reported concerns about their safety.
The officers, and another man, 61, were in the communal area of a block of flats when a suspect with a knife appeared.
All three were assaulted and had to be taken to hospital to receive treatment.
The 61-year-old suffered stab injuries, with a report on his condition still pending. One officer suffered slash injuries that were non-life threatening.
Police say a man was arrested at the scene on suspicion of assault, while two other people were also arrested as part of the investigation. All three remain in custody.
Police said a crime scene remains in place, and at the this stage the incident was not thought to be terrorism-related.
Anyone with any information is urged to call 101.