Although the attackers were also dead, authorities raced to determine whether they had accomplices, and Prime Minister Theresa May yesterday warned that the country faced a new threat from copycat attacks.
The country's major political parties temporarily suspended campaigning with only days to go before the general election. May said the vote would take place as scheduled Thursday because "violence can never be allowed to disrupt the democratic process."
Three men then got out of the vehicle with large knives and attacked people at bars and restaurants in nearby Borough Market until they were shot dead by police.
"They went 'This is for Allah,' and they had a woman on the floor. They were stabbing her," witness Gerard Vowls said. Florin Morariu, a Romanian chef who works in the Bread Ahead bakery, said he saw people running and some fainting. Then two people approached another person and "began to stick the knife in ... And then I froze and I didn't know what to do."
Also Read
"There was a car with a loudspeaker saying 'go, go' and they (police) threw a grenade. ... And then I ran," he said. London police said officers killed the attackers within eight minutes of arriving at the scene. Eight officers fired some 50 rounds, said Assistant Commissioner Mark Rowley, the force's head of counterterrorism.
Islamic State's statement today from its Aamaq news agency claimed the group's "fighters" were responsible, according to the SITE Intelligence Group. IS has urged supporters to weaponize vehicles in attacks against the West.
The three attackers Saturday were wearing what appeared to be suicide belts, but the belts turned out to be fake.
Investigators were working to determine whether others assisted them, Rowley said.
A bystander was also wounded by the gunfire, but the civilian's injuries were not believed to be critical.
Canadian Prime Minister Justin Trudeau said a Canadian was among the dead. A French national was also confirmed dead.
Counterterrorism officers raided several addresses in Barking, an east London suburb, and arrested 12 people there yesterday, police said.
Neighbors at the site of one raid in Barking said a man who lived there resembled one of the attackers shown in news photographs.
"He's lived here for about three years," Damien Pettit said. "He's one of our neighbours. I've said hello in passing more than 50, 60 occasions. He has two young kids. He was a very nice guy."
The rampage was the third major attack in Britain in the past three months, including a similar vehicle and knife attack on Westminster Bridge in March that left five people dead.
On May 22, a suicide bomber killed 22 people and injured dozens at an Ariana Grande concert in Manchester, in northwest England. Grande and other stars performed last night at a benefit concert for victims under tight security in Manchester.
The Islamic State group claimed responsibility for the Manchester bombing, but there was no immediate claim of responsibility for the London attack, which the prime minister linked to Islamic extremism.
May said the attacks were not directly connected, "but we believe we are experiencing a new trend in the threat we face" as "terrorism breeds terrorism" and attackers copy one another. She said five credible plots have been disrupted since March.
Home Secretary Amber Rudd said yesterday that the level would remain at severe because police believe there are no perpetrators still on the loose.
London Bridge and a large area on the south bank of the River Thames remained cordoned off yesterday, and police told people to avoid the area.
Hours earlier, the area packed with bars and restaurants around the foodie magnet of Borough Market had been a scene of panic, as people barricaded themselves in pubs and restaurants or fled through the streets.
Renan Marquese, a sous-chef at a tapas restaurant, said he was working when he heard chaotic sounds outside.
"When I open the door I see three dead people on the floor," he said. "People running everywhere, police shouting to run away."
He said that he helped a man and his partner, even taking the woman into his arms because she was too upset to walk properly. He said it took him 20 minutes to carry her across the bridge, stumbling all the way.
Amid the violence and fear were stories of compassion and heroism. The British Transport Police said one of their officers, among the first to arrive, took the attackers on armed only with his baton and was seriously wounded. He was later described as being in stable condition with injuries that were not life-threatening.
Witnesses described how passers-by threw chairs and beer glasses at the attackers in an attempt to stop them. Richard Angell, who was in a restaurant, said he looked out and saw "a guy who is throwing a table at somebody, and it's very unclear about what is happening. And it turns out to be a heroic guy who saw what was happening and just bombarded these terrible cowardly people with stuff."
Vowls also saw people striking back at the attackers and said he joined in.
"I went 'Oi, terrorists, cowards, Oi!'" he told The Associated Press. Then he picked up a chair.
"I chucked it, but I think I missed one of them, and then I picked up a stool, and I threw it at him. And he looked at me. He started running towards me, and then he decided not to. "Then I was screaming at them, picking up bottles from a beer barrel. I was just throwing it at them, trying to get them to chase me so I could get them out into the main road where the police could see them and obviously take them down.
Disclaimer: No Business Standard Journalist was involved in creation of this content