Following the atrocity, Mr Trump wrote: “At least 7 dead and 48 wounded in terror attack and Mayor of London says there is ‘no reason to be alarmed!'”
He seemed to be referring to Mr Khan’s earlier statement that “Londoners will see an increased police presence today and over the course of the next few days. There’s no reason to be alarmed”.
Strongly condemning the attack in London Bridge and Borough Market, the mayor appealed to people to remain vigilant, while at the same time assuring them that the capital is “one of the safest global cities in the world.”
At least 7 dead and 48 wounded in terror attack and Mayor of London says there is “no reason to be alarmed!”
— Donald J. Trump (@realDonaldTrump) June 4, 2017
In response, a spokesperson for the London Mayor said Mr Khan “is busy working with the police, emergency services and the government to coordinate the response to this horrific and cowardly terrorist attack”.
“He has more important things to do than respond to Donald Trump’s ill-informed tweet that deliberately takes out of context his remarks urging Londoners not to be alarmed when they saw more police – including armed officers – on the streets,” the spokesperson said.
Mr Trump also tweeted about political correctness and brought gun control into the debate, in light of the fact the attackers “used knives and a truck”.
Earlier in the day, the President had sent a tweet following initial reports of the attack, telling the UK that Americans “are with you” and “we need to be smart, vigilant and tough”.
But he was criticised for turning attention back to the US and his immigration crackdown by adding: “We need the courts to give us back our rights. We need the Travel Ban as an extra level of safety!”
We need to be smart, vigilant and tough. We need the courts to give us back our rights. We need the Travel Ban as an extra level of safety!
— Donald J. Trump (@realDonaldTrump) June 3, 2017
He went on to say: “Whatever the United States can do to help out in London and the UK, we will be there.”
He also retweeted an early unconfirmed report on the attack from a US news aggregation website.
Former Labour spin doctor Alastair Campbell called the President’s opportunistic tweet “classless”, writing: “Merkel, @EmmanuelMacron make well pitched reactions to London attacks @potus relies on unconfirmed reports to promote travel ban #classless”.
— Alastair Campbell (@campbellclaret) June 4, 2017
The US state department has said that America “condemns the cowardly attacks” and was “ready to assist”.
Theresa May said there is far too much tolerance of extremism in the UK and it is time to be more robust in tackling it.
Speaking in Downing Street following the atrocity, the Prime Minister said it was time to say “enough is enough”.
Labour leader Jeremy Corbyn said: “Brutal and shocking incidents reported in London. My thoughts are with the victims and their families. Thank you to the emergency services.”
Meanwhile Japan has warned its citizens to avoid potential terror targets in London, following the attacks.
The nation issued a travel advisory mentioning sightseeing spots, department stores, markets, concert venues and political rallies.
Japan’s foreign ministry warned visitors to the UK should “pay close attention to the surroundings, and leave quickly if any suspicious signs are seen”.
French Prime Minister Emmanual Macron tweeted: “In the face of this new tragedy, France is more than ever at the side of the UK. My thoughts are with the victims and those close to them.”
Canada’s Prime Minister Justin Trudeau tweeted: “Awful news from London tonight. We’re monitoring the situation.”
Australia’s foreign minister Julie Bishop described the incidents as a “shocking situation”.
She said in a statement: “We stand ready to support the British government as it responds to these attacks and our thoughts are with those injured and their families.”
European Commission leader Jean-Claude Juncker said: “Following latest London incidents with horror. Thoughts and prayers are with the victims and their families. Please stay safe.”