A hero taxi driver has revealed how he tried to knock down three men armed with 12-inch hunting knives who reportedly stabbed pedestrians after mowing down up to 20 people with a white van on London Bridge.
Witnesses reported hearing "rapid gunfire" amid reports that least seven people have been stabbed, leaving bodies "strewn" on the road in central London. One of the casualties is reportedly a police officer.
But amid the horror a cabbie - who said he saw the men brandishing "long blades" stabbing "randomly" on Borough High Street - spun around his vehicle and attempted to halt the terror, reports Daily Mail.
Speaking to LBC, he said: "I thought, 'I'm gonna try and hit him, I'm gonna try and knock him down'."
"I spun the cab round, I was about to ram one of them, but he side-stepped and three police officers came running towards them with their batons drawn.
"I was shouting at everybody, just get away from the area, stay back, just run the other way. There were a good few hundred people out there."
The driver, who did not identify himself, continued: "He's veered across the road towards the right hand of where Southwark Cathedral is and rammed it where the steps are.
"He just rammed it towards them, wedged it in between the lamppost and the steps and so he's hit people there.
"They've jumped out of the van and started stabbing people randomly. There was a scattering of people."
One witness said she saw three people with what appeared to be their throats cut on London Bridge amid the "utter chaos".
There are unconfirmed reports of gunfire on Southwark Street.
Others said they saw three men, described as being "of Mediterranean origin", jump out of the van and began "randomly stabbing people" along Borough High Street with 12-inch long knives.
The car, believed to be a B&Q vehicle, was reportedly veering in an "S shape" at 50mph across the bridge and has driven towards the Shard and is south of the river. The drivers have not been caught.
Terrifying footage from the scene shows police officers shouting "Clear the scene now!" as panicked pedestrians flee.
The bridge is in lock down and the area around it is closed with bus routes being diverted, as armed police and a bomb squad attend the scene and boats search the water.
Police are 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.
One eyewitness who wished to remain anonymous told MailOnline: "I was in Arabica restaurant with a friend in borough market.
"Suddenly there was commotion and people were screaming. Security guards were yelling at people to get back from the window. About 50 people piled into the restaurant.
"Then I heard two separate bursts of gunfire and people rushed into the restaurant kitchens to hide. It was utter chaos.
"Some people tried to leave the kitchens via the back door but some of us tried to keep people calm. We hid for 45minutes and then were evacuated from the market by armed police."
Pictures of the white van will be circulated across London.
Tony Murphy, who has a flat opposite Southwark Bridge, said he heard "rapid gunfire".
He said: "I'm actually former military. I heard what was significant gunfire.
"At first I thought it was fireworks but it was so rapid I recognised what it was.
"It went on for quite a long time. The response took about 10 minutes. I immediately text my family and they said they heard it. It was tremendous gunfire."
Holly Jones, a BBC reporter at the bridge when the incident happened, said a van had swerved off the road into a crowd of pedestrians.
"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."
Ms Jones later reported seeing a man being arrested by police. She said he was handcuffed and had his shirt off.
Witness Alessandro told the BBC that he saw a van at the end of London Bridge with no driver inside and described the "five or six" people hit as "very young".
He said: "I was going up the stairs of London Bridge Station. I saw this van going left and right trying to hit as many people as he could. I tried to help people.
"At the end of the bridge we saw a van but we didn't see anyone in the van.
"I think [the driver] went to the end of London Bridge. We didn't see the van stop because we were trying to help people.
"Everything was confused. There were five or six people [hit]. Three of them were conscious. One of them was not talking at all. He was just down.
"The five or six people we tried to help were really young."
Another taxi driver named only as Paul said: "I was just going over London Bridge and on the left hand side it looked like someone had been knocked off a bike.
"A few yards on I saw another person laying down and a woman screaming.
"A few yards on from that there was a couple of bodies on the right hand side."
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 is 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."
London Bridge and the area around it has been closed due to a "major police incident", TFL said.
London Bridge station has been closed and no trains are expected until the end of service.
Holly, who said she was just two metres away from being hit by a white van, described the chaos on London Bridge after the attack.
She told Radio 5Live: "I was probably two metres away. I saw it hit the people in front of me. I feel just so lucky now.
"It was all a blur, but as much as I can remember it was a male on their own [driving the van]. There are five people on the floor being attended too. There are loads of city police officers helping and boats on the Thames searching."
The BBC's Holly Jones spoke to a French woman who had been injured in the incident.
She told Ms Jones: "I don't know where those other two people are. So the police are checking the Thames.
"They were right near the edge of the bridge. It looks potentially they could have been thrown over."
Witnesses told the BBC that a white van veered off the road on London Bridge and hit five or six people.
One witness wrote on Twitter: "Passerby says 15-20 people have been run over. Another says 7 or 8."
"Horrific scene at London Bridge. Bodies strewn over the pavement, B&Q van mounted the pavement. I feel sick," one witness wrote.
"On a boat travelling under London Bridge. Buses stopped. Police lights everywhere and boats checking the water. Please let everyone be okay!" another added.
"Police are dealing with a major incident and all routes are being diverted."
The Metropolitan Police posted on Twitter: "We are dealing with an incident on London Bridge, when we have more information we will update this twitter feed."
London Bridge is closed both ways due to a police incident, Tfl said, warning the public to avoid the area.
Scotland Yard said officers were at the scene and they would update with further information.
London Ambulance said multiple resources were attending the area.