Donald Trump has hit out at the NHS, claiming it is "going broke and not working".
The US president made the attack as he targeted Democrats pushing for a British-style universal health system.
He said "thousands of people are marching" in the UK because of concerns about the state of the NHS.
His comments came shortly after former Ukip leader Nigel Farage appeared on one of the president's favourite US TV news shows to talk about the NHS.
Mr Farage's appearance on Fox And Friends appeared to be the reason for Mr Trump's Twitter comment.
In a follow-up message, the president thanked the show for "exposing the truth".
Mr Trump's social media messages came after a crowd of thousands chanting "Save the NHS" descended on Downing Street on Saturday to demand more funding for the health service.
Marching through central London to draw attention to the NHS funding shortage, people carried placards urging "Kick the Tories out" and "More staff, more beds, more funds".
The demonstration, called NHS In Crisis: Fix It Now, was organised by the People's Assembly and Health Campaigns Together.