Police were responding to multiple 999 reports of a man with a firearm in Creek Road.
The police watchdog has opened an investigation after a man was shot by police during a “serious incident” in Greenwich.
Scotland Yard said a police firearm was discharged and the man sustained a gunshot injury.
A spokesman for the Independent Office for Police Conduct (IOPC) said: “Today, shortly after 4pm we were notified by the MPS that a man had received a gunshot injury as the result of a police shooting during an incident in Greenwich, south London.
“We have begun an independent investigation. Our investigators have been sent to the scene and (we have started) the post-incident procedures to start gathering evidence.”
Police said the incident was not thought to be terror-related.
His injuries are not believed to be life-threatening and he was transferred to hospital after being treated at the scene, the force added.
In a statement, the Met said: “While the investigation is in its early stages, this incident is not believed to be terror-related or that there is an ongoing threat to the wider public.”
Gemma Daly, 31, from Whitstable, but staying in Greenwich, said she heard some shouting and then “a big bang” which she believes was a gunshot.
She said she heard police sirens straight away, adding that the emergency services then started arriving.
“Police were attending to a man on the side of the bridge,” she said, adding that he was “clearly injured”.
“They removed his clothing”, she said, describing how “a lot of people” were working on the man before he was put on a stretcher.
Ms Daly said police “started to go around” a silver car, which was still on the bridge.
Pictures of the scene showed emergency vehicles, including police cars and an ambulance, stopped in the middle of the road.
A London Ambulance Service spokesperson said they had sent multiple resources including medics from London’s Air Ambulance to the scene.
They said: “We treated a man at the scene and took him as a priority to a major trauma centre.”
The Met said significant cordons remained in place on Friday evening and urged the public to avoid the area.