Despite confirmation that the attacker was shot by police, it is now unclear whether he is the reported fatality, as the Metropolitan Police earlier reported that they had detained the suspect.
British police say several people have been injured near to London Bridge, and a man has been detained.
Image copyright Alexander Carr Image caption Police are responding to the stabbing "as though it is terror-related" What did witnesses see?
Metro Police are also urging for "common sense and restraint" in circulating videos and pictures from the incident on social media until facts are gathered.
This is one of the hero bystanders who took the knife away.
In the immediate aftermath of the incident, it was reported that armed police had shot a man dead on the bridge.
Police evacuated London Bridge station and the surrounding area.
The police officers can be heard ordering the terror suspect to surrender.
He is returning to Downing Street from his constituency.
Interior minister Priti Patel said she was "very concerned" at events.
The bridge was closed off, with buses and traffic on London Bridge at a standstill.
Another video, in which gunfire is possibly audible, shows people hurrying across the bridge in a southbound direction with northbound traffic backed up on the opposite side of the road.
A video has emerged showing members of the public tackling a man to the ground in the incident at London Bridge.
"Then police ran over with guns, screaming", before shooting the man, Griffiths added.
Witnesses have spoken to the BBC about what they saw. It seemed like there was something in his hand.
"One man has been shot by police".
'They got everyone back including one guy they had to pull off the man as he held him down.
The Sun reports that a man in a suit got the weapon away from the knifeman then walked away from the scene.
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