“Police were called at 1:58 p.m. to a stabbing at premises near to London Bridge,” the force said Friday.
The London Ambulance Service said a number of crews were at the scene and a “major incident” had been declared.
Images and video on social media show emergency vehicles on the bridge, and onlookers reported hearing what sounded like gunshots at the scene.
Jinnat Ui Hasan told CNN he was in a meeting in a building near the incident when he heard “more than five” gunshots.
Elsewhere, Stevie Beer, 26, told CNN that her place of work which overlooks the bridge was in lockdown.
Police earlier told CNN it was dealing with a “dynamic situation.”
This is a breaking story. More to follow.