A number of people are believed to have been injured after a stabbing at London Bridge, police have said.
The Met said one man had been shot by police and it was treating the incident “as though it is terror related”.
The force earlier said it had detained a man. London Ambulance Service has declared a “major incident”.
The BBC’s John McManus, at the scene, said he had seen a group of men in a fight on the bridge. Police then arrived and shots were fired, he said.
British Transport Police said London Bridge station was currently closed and no trains would be stopping there.
Police have advised people near the scene to follow directions from officers on the ground.