Washington DC - Major American television networks on Monday suspended their involvement in a rotation of broadcasters covering President Donald Trump, as three leading news outlets went to court over being banned from the White House.

CNN and MS NOW, along with news outlet Politico, filed suit after Trump last week ordered them to be barred from the presidential complex.

"This ban could not be a more direct assault on the First Amendment nor a more blatant violation of our most fundamental constitutional principles," the organizations said in a court filing.

Shortly afterward, the five major US broadcasters said they were halting "pool" coverage of the White House in solidarity with CNN.

Donald Trump Trump calls the US press "a threat to our national security" that "must be stopped"

CNN had been scheduled to serve Monday as the White House TV pool, a rotating assignment in which a broadcaster films on behalf of all television outlets for the day.

"The public has a vital interest in receiving accurate, independent information about its government. No administration should restrict a news organization because it objects to its reporting," ABC, CBS, CNN, Fox, and NBC said in a statement.

The boycott means there will be no pooled coverage of Trump's travel to the United Nations General Assembly in New York on Monday, where he is due to meet a series of world leaders.

Trump was unrepentant, with the 80-year-old Republican branding the media a "cancer" and a threat to national security.

"The White House is not instituting an assault on the Free Press, something which I cherish," Trump said on his Truth Social network.

"It is instituting an assault on the FAKE NEWS, something that has grown like Cancer in our beloved United States of America."