Donald Trump has criticised London's mayor, just hours after last night's terror attacks in the city.

In his first reaction, he seemed to link the attack that claimed seven lives, with his legal battle to implement a travel ban on citizens from 6 Muslim-majority countries.

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

Then he tweeted his support for the people of London.

Later, in an apparent comment on the attack, the US President Donald Trump tweeted: "We must stop being politically correct and get down to the business of security for our people."

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

Next he took aim at London's mayor Sadiq Khan, who earlier had tried to reassure Londoners that everything was being done to secure the city.

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