Donald Trump has sparked fresh health concerns after appearing to forget how old America is in an embarrassing blunder during a press briefing. The US President was discussing plans to appoint Louisiana governor Jeff Landry as special envoy to Greenland at his Mar-a-Lago resort on Monday when he mistakenly suggested America  had existed 300 years ago. Mr Trump explained his decision to appoint Mr Landry to the role after the latter openly said he would like the self-governing Danish island to become part of the US by insisting his country “needs it for national protection”.

“They have a very small population,” he continued. “And I don’t know, they say Denmark, but Denmark has spent no money. They have no military protection. They say Denmark was there 300 years ago or something, with a boat. Well, we were there with boats, too, I’m sure.” The president’s forgetfulness comes amid preparations to celebrate America’s 250th birthday next year, marking the adoption of the Declaration of Independence on July 4, 1776, widely considered the birth of the nation.

Mr Trump himself has been active in announcing celebrations to mark the landmark date, including the Patriot Games, a new athletic competition featuring “one young man and woman from each state and territory”.

He has pledged to give America “the most spectacular birthday party the world has ever seen”, with other festivities including a ‘Spirit of America’ parade, honouring fallen soldiers, and a UFC fight on the White House’s South Lawn.

However, despite his insistence of “acing” health checks, fears about Mr Trump’s cognitive and physical abilities have increasingly reared their head in recent months.

He made headlines when he appeared to fall asleep during a Cabinet meeting last week, leading California governor Gavin Newsom to label him “Dozy Don”.

Mr Trump has also mixed up Albania and Armenia on a number of occasions while discussing the conflict between Armenia and Azerbaijan.

The White House confirmed he had been diagnosed with chronic venous insufficiency after speculation ran wild over photos of bruises on one of the president’s hands – something press secretary Karoline Leavitt blamed on shaking lots of people’s hands.

Ms Leavitt also announced the results of a magnetic resonance imaging (MRI) scan in October, which she said was part of his “routine physical examination” and showed he “remains in exceptional physical health”.