Three men wearing mock suicide vests have been shot dead after they drove a van through crowds on London's streets and attacked citizens with knives, killing six and leaving a further 48 in hospital.
The United Kingdom is waking up to the Sunday morning news that suspected Islamic terrorists have attacked their nation for the second time in as many weeks after 22 people were killed at an Ariana Grande concert in Manchester.
Up to nine people are reported dead after a terror attack in London, including three terrorists.
A further 48 people have been taken to five hospitals around the British capital following the Saturday night attacks in the city's centre.
The attack comes only days before the nation heads to the polls for a general election, prompting the ruling Conservative Party to suspend its national campaign.
The attackers brought carnage to the streets of the British capital on Saturday night, stabbing a police officer and revellers with 30cm knives, reportedly shouting "this is for Allah".
The terror attacs were carried near London Bridge and Borough Market. Another incident in Vauxhall was later confirmed to be unrelated.
The trio were pictured wearing what appeared to be explosive vests, with Scotland Yard later confirming they were hoaxes.
The suspects were confronted and shot by responding police at Borough Market within eight minutes of the first call being made.
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The terror unfolded as officers arrived at the scene shortly after 10pm to reports of a vehicle striking pedestrians on London Bridge.
The white van then continued to drive to Borough Market where the three men left the vehicle and began stabbing people, including a British Transport Police Officer.
Witnesses reported seeing the vehicle plough into victims about 90 km/h.
"A white van driver came speeding ... veered off the road into the crowds of people who were walking along the pavement," according to BBC reporter Holly Jones who was at London Bridge.
olice officers on Borough High Street. Source: AP
"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."
“About five people were being treated for injuries after the vehicle mounted the pavement and hit them,” she said.
She said the van, which was travelling from the direction of central London, headed towards the south side of the river.
An image posted to social media appeared to show a man with canisters strapped to his body. Photo: Supplied
Ms Jones later reported seeing a man being arrested by police. She said he was handcuffed and had his shirt off.
The armed men then stormed pubs at nearby Borough Markets and started attacking patrons, with reports suggesting some had their throats cut.
Police said three attackers had been shot and killed within eight minutes of the first emergency call shortly after 10pm.
Families caught up in the chaos on the streets of London. Source: AP
The suspects were wearing what looked like explosive vests but these were later established to be hoaxes.
Source: AP Images
One of the men suspected of being behind the attack has been shown in a photograph lying on the ground with the hoax canisters strapped to his body after being shot by police, the BBC says.
The possible attacker was shown on the ground outside the Wheatsheaf pub in Borough Market near London Bridge.
Another man was seen lying on the ground a short distance away in the photograph.
Source: AP Images
Later accounts said there was a series of "intense gunfire" heard in the area.
Two explosions have been heard outside the Sun newspaper's offices near London Bridge.
The blasts, which occurred at 1:23am and 1:25am local time on Sunday are believed to have been controlled explosions carried out by police, the newspaper said.
A third explosion was heard a few minutes later near The Shard, an iconic skyscraper close to London Bridge.
Source: AP Images
Pictures show medical staff attending to apparent victims of the attack and a helicopter buzzing just metres over London bridge, one of the major arteries in the City business district.
Police responded rapidly with dozens of emergency vehicles and authorities led shellshocked members of the public away from the scene with their hands on their heads.
The attack came more than a week after a suicide bomber killed 22 people at a concert in the northern city of Manchester and days ahead of the June 8 election, where security is a major theme.
It also recalled an attack on Westminster Bridge when 52-year-old British Muslim convert Khalid Mahmood rammed his car into pedestrians before crashing into the barriers surrounding parliament and then stabbing a police officer to death.
London's transport authority said London Bridge rail station had been closed at the request of the police.
Three major London hospitals were on lockdown after the attacks.
Police also responded to what has since been confirmed as an unrelated incident in Vauxhall.