Donald Trump has lashed out at Sadiq Khan, the Mayor of London, over his reaction to the terrorist attacks at London Bridge on Saturday night (3 June).
"We must stop being politically correct and get down to the business of security for our people. If we don't get smart it will only get worse," the US President wrote on Twitter on Sunday afternoon.
A second tweet read: "At least 7 dead and 48 wounded in terror attack and Mayor of London says there is 'no reason to be alarmed!'"
Trump went on to observe that the incident in London had not sparked a debate on gun control.
"Do you notice we are not having a gun debate right now? That's because they used knives and a truck!" he wrote.
Many people on social media reacted angrily to Trump's comments, accusing him of being unpresidential and taking the London Mayor's comments out of context.
Khan had said during an interview with Sky News: "Londoners will see an increased police presence today and over the course of the next few days. There's no reason to be alarmed."
Khan had also condemned the attacks "in the strongest possible terms" and said he was "grieving" for the victims.
In a message of defiance, he insisted the 8 June general election must go ahead as planned and that the terrorists "would not win". He went on to ask people to remain vigilant.
Trump's comments were condemned by Labour parliamentary candidate David Lammy, who described them as "cheap, nasty and unbecoming of a national leader".
Other social media users supported Trump's comments, however, and urged for a reinstatement of his controversial travel ban.
This is not the first time Trump has criticised Khan, who became the first Muslim mayor of a major European city when he was elected into office in May last year.
Last year, Khan accused Trump of having an "ignorant view of Islam" when the then US Presidential candidate proposed a travel ban for all Muslims entering the United States.
"Donald Trump's ignorant view of Islam could make both our countries less safe – it risks alienating mainstream Muslims around the world and plays into the hands of the extremists," Khan said at the time.
"Donald Trump and those around him think that western liberal values are incompatible with mainstream Islam – London has proved him wrong."
Police say Saturday's attack saw seven people killed – on top of the three dead terrorists – and at least 48 injured.
The incident saw the assailants drive a van into pedestrians on London Bridge at about 10pm before knifing people in nearby Borough Market.
All three assailants were shot dead by police within eight minutes of the first 999 call, police said.
Officers made 12 arrests in connection with the incident during raids in Barking the following morning.
Theresa May also chaired an emergency Cobra meeting with ministers on Sunday morning in response to the incident.
She said outside Downing Street that it was time to say "enough is enough" when it comes to tackling terrorism.
"We cannot and must not pretend that things can continue as they are," she said, adding that "difficult" and potentially "embarrassing" conversations were needed within the UK about dealing with the spread of extremism.
She said the London Bridge attacks were not directly connected with the bombing last month in Manchester or March's attack in Westminster, which saw British-born terrorist Khalid Masood kill five people when he drove into pedestrians and launched a knife attack.
May said the country is "experiencing a new trend in the threat we face as terrorism breeds terrorism".