Police had earlier said it was called to a stabbing near London Bridge at around 2 p.m. local time. Video footage published on social media showed members of the public being wrestled off a man by police, before shots are then fired at the man by one officer.

Metropolitan Assistant Commissioner Neil Basu, who acts as the U.K.’s top counter-terrorism officer, subsequently told reporters on the steps of Scotland Yard that the man had died at the scene. Basu added that police believe that the dead suspect had a “hoax device” strapped to his body.

The anti-terror chief said he was not yet in a position to update on the nature of injuries to other people.

A Cabinet Office Briefing Rooms meeting, often referred to as COBRA, is now underway involving security services, counter-terrorism specialists and the U.K. Prime Minister Boris Johnson.

Panicked situation

Authorities closed off London Bridge and warned commuters at the nearby train station not to travel on the bridge or along Tooley Street. Traffic on the bridge was at a standstill with a truck parked at a 90-degree angle across the road. The train station was later closed.

In interviews with CNBC, commuters spoke of a panicked situation during which people were told to initially evacuate London Bridge station before being asked to remain on the platforms.

A tweet from the London Ambulance Service described it as a major incident. U.K. leader Boris Johnson tweeted that he was being kept updated on the incident. He later thanked the emergency services and members of the public for their “immense bravery in responding to this suspected terrorist attack at London Bridge.”

“This is an appalling incident and all my thoughts are with the victims and their families,” the U.K. leader said.

Two years ago and just yards away from Friday’s incident, eight people were killed and 48 were injured in a terrorist vehicle-ramming and stabbings along London Bridge.

Earlier this month, the country downgraded its terrorism threat level from “severe” to “substantial.”