"Police then quickly arrived, including armed police, and then a number of shots were fired at this man".
Met Police will be making a statement at 4pm.
Eyewitness Coralie, who asked Yahoo News to withhold her last name, said over WhatsApp that she saw "two, three people stabbed" at Fishmongers' Hall on Friday where she was working. The UK's counter-terror officials have taken over the investigation now that the incident has been declared as terror related.
The man was later shot dead by police.
Several people were stabbed by the knifeman on London Bridge before he was grappled to the ground and disarmed by members of the public.
Police said one man had been detained, and witnesses reported seeing a man shot by armed officers.
The incident happened on the north side of the bridge.
Footage posted on social media showed armed officers apparently pulling civilians off a person lying on the ground on the bridge before firing at him from close range.
The response from officers led scores of people to run down St Thomas Street, though the exact cause of the incident is still unknown. It was quite hard because cars were passing in the way of what was happening.
"Police have now cleared the bridge, everybody has been told to move back and now on the northern side of the bridge, but there are more shots going on".
'They got everyone back including one guy they had to pull off the man as he held him down.
London Bridge station was closed.
There, police detained the alleged stabbing suspect and are reporting that "a number of people" have been "stabbed" and are injured.
BBC reporter John McManus said several men were seen fighting on the bridge.
"One man has been shot by police".
The Sun reports that a man in a suit got the weapon away from the knifeman then walked away from the scene.
Police have cordoned off the bridge.