In March, in a attack similar to Saturday's, a man killed five people after driving into pedestrians on Westminster Bridge in central London. The White House said the president "praised the heroic response of police and other first responders and offered the full support of the United States government in investigating and bringing those responsible for these heinous acts to justice".
"I'm appalled and furious that these cowardly terrorists would target innocent Londoners and bystanders enjoying their Saturday night. It will only be turned around by persuading people are values are better".
Boats on the River Thames helped evacuate the area, which is popular with tourists.
The Metropolitan Police force declared the attacks "terrorist incidents".
President Donald Trump has sent a flurry of early morning tweets in the wake of the London attacks - criticizing the city's mayor and bemoaning what he says is political correctness when it comes to national security.
They also came just days before Britain goes to the polls for a general election on Thursday.
"The Conservative Party will not be campaigning nationally today". The driver said something bad is happening here.
"They are bound together by the single evil ideology of Islamist extremism that preaches hatred, sows division, and promotes sectarianism", she said. The BBC showed a photograph of two possible attackers shot by police, one of whom had canisters strapped to his body. "But these were later established to hoaxes".
Bill English, prime minister of New Zealand, said his country's "thoughts are with the victims of today's attack, along with their families and friends".
"They kept coming to try to stab me. They put pressure on the stab wound". I've been walking around for an hour and a half crying my eyes out.
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"People managed to escape through the rear door so she saved maybe 20 people's lives".
Labour Leader Jeremy Corbyn said on Twitter: "Brutal and shocking incidents reported in London. It was a rampage really", he said, adding that he also heard a shout of: "This is for Allah".
Mrs May said the United Kingdom has made "significant progress" in disrupting plots and protecting the public since the emergence of the threat from Islamist-inspired terrorism. As a documentary filmmaker, though, his instincts were to keep going.
The 25-year-old said that at first, "it didn't look too risky".
They were confronted and shot by police at Borough Market within eight minutes of the first call being made. They advised that this was a better option than negotiating or surrendering to attackers.
At Borough market, which in the evenings is busy with bars, witnesses said they saw a man with a large blade.
Jones also said that she saw a man being arrested shortly afterward.
"We would ask the public to remain calm, vigilant and alert, and to report any suspicious behaviour to the police on 0800 789 321".
May confirmed the attack "is being treated as a potential act of terrorism" and said her thoughts were with "those who are caught up in these terrible events".
In the morning hours of Sunday, as Europe woke to news of yet another deadly terrorist attack, worldwide news media blanketed coverage of last night's terror assault in London, its ongoing investigation and the reactions of government leaders.
The London Bridge area remains cordoned off and London Bridge station remains closed.
This is, as we all know, the third terrorist attack Britain has experienced in the last three months.