President Donald Trump waves as he steps out from Air Force One in Reno, Nevada: REUTERS

A group of psychiatrists has written to Congress to warn Donald Trump poses a "clear and present danger" to the world.

Among them is Dr Bandy Lee, of Yale University, who is also reportedly consulting with Democratic members of Congress on setting up an expert panel to give advice on the President's mental health.

She is concerned by Mr Trump's "dangerousness", Dr Lee told USA Today.

The group's letter, sent to members of both parties, said: "It no longer takes a psychiatrist to recognise the alarming patterns of impulsive, reckless, and narcissistic behaviour — regardless of diagnosis — that, in the person of President Trump, put the world at risk.

"We now find ourselves in a clear and present danger, especially concerning North Korea and the President’s command of the US nuclear arsenal."

It comes after Democrats proposed creating an 11-member, cross-party Oversight Commission on Presidential Capacity which would be responsible for examining the US president’s mental and physical health.

First tabled by Maryland congressman Jamie Raskin, and now backed by more than two dozen members of the House, the bill would see Mr Trump or any other US president forced from the Oval Office is he or she is deemed to be mentally or physically unfit for the role.

Discussion of Mr Trump's fitness to lead has intensified in the days since his extraordinary address to supporters in Phoenix, Arizona.

The President blasted "damned dishonest" journalists and took aim at both the state's Republican senators in a rambling speech, having abandoned his teleprompters.

He also revisited his various statements in the wake of far-right violence in Charlottesville, Virginia, reading portions to prove he had condemned white supremacists and had been misrepresented by the media.

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