Witnesses have described scenes of chaos and confusion with London police responding to two major incidents in the city.
British Transport Police say there are reports of multiple casualties following major incident on London Bridge, while another incident is occurring at Borough Market
Holly Jones, a BBC reporter was on London Bridge when she saw a van swerve off the road into a crowd of pedestrians just after 10pm on Saturday night.
“A white van driver came speeding – probably about 50mph – veered of the road into the crowds of people who were walking along the pavement,” she told BBC News.
“He swerved right round me and then hit about five or six people. He hit about two people in front of me and then three behind.
She said she saw about four severely injured people.
Ms Jones said police were on the scene within two minutes, quickly followed by ambulances.
Police boats were searching the river – apparently looking for people who may have been thrown off the bridge.
She said that among the injured was a French woman who told her she did not know where the two people who had been with her were.
“She told me in French, ‘I don’t know where those two other people are’. So the police checking the Thames,” Ms Jones said.
“They were right near the edge of the bridge. It looks potentially they could have been thrown over.”
Police were treating injured people and carrying them away at the end Thrale Street. Members of the public were told by police to “run as fast as they could” westbound.
Nick Archer, who was in the London Bridge area, told Sky News: “We came out (of a bar) on to the road and looked and looked to my left and there as a guy, I thought he was just drinking but he was lying on the floor.
“And then a couple of seconds later, about three police vans flew past. He looked in a bad way.”
Tony Murphy, who lives near the area, told Sky News he heard the sound of gunfire.
“I thought at first it was fireworks then I recognised it was significant gunfire and that was the first instance,” he said.
“After that (came) the whole shooting match of ambulances and police.
“There was rapid fire because that’s why I thought it was fireworks.”
Australian Labor senator Sam Dastyari, who was dining in the areas, described the scene as one of panic, fear and chaos.
“It’s graphic. There is no other way of describing it. It’s confronting. The sheer sense and wave of panic that runs through people,” he told Network Nine.