MS NOW, CNN and Politico have sued US President Donald Trump, seeking to overturn his decision to bar journalists from the three media organisations from the White House.

The lawsuit was filed on Monday after reporters from the outlets were denied access to the White House on Saturday, a day after Trump announced the ban.

The media organisations argued that the decision violates the First Amendment and undermines their ability to report on the president and his administration.

“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 lawsuit stated.

The outlets said the restrictions had already “severely impeded” their ability to cover Trump and his administration.

“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 lawsuit says, arguing that the ban has already “severely impeded the ability of” the three outlets to cover Trump and his administration.

“Presidents from the earliest days of the Republic have disagreed with and complained about the tenor and content of press coverage of their administrations,” notes the civil complaint in U.S. District Court in Washington.

The lawsuit also argued that the Constitution protects the “liberty and property interests” of news organisations and White House reporters in their press credentials and the access those credentials provide to cover the administration on behalf of the public.

Trump announced the ban in a Truth Social post on Friday, accusing the three outlets of publishing what he described as “fiction and lies” about him.

He also warned that other media organisations could face similar restrictions, writing, “Other Fake News Media Outlets to follow.”

“No official can deprive Plaintiffs of those interests on a whim — with no notice, no process, and no warning — as the President did here.”

Trump cited what he called the outlets’ “cumulative stories” about his administration, adding, “You get sick of it.”

Trump announced the ban in a Truth Social post on Friday, accusing the three media organisations of publishing what he described as “fiction and lies” about him.

He also warned that other media outlets could face similar restrictions, writing, “Other Fake News Media Outlets to follow.” Trump pointed to what he called the outlets’ “cumulative stories” about him, adding, “You get sick of it.”

However, after the lawsuit was announced on Monday morning, Trump defended the decision in another Truth Social post, saying, “The White House is not instituting an assault on the Free Press, something which I cherish.”

“It is instituting an assault on the FAKE NEWS, something that has grown like Cancer in our beloved United States of America,” Trump wrote. “It is corrupt, purposeful, pervasive, fully coordinated, and totally out of control.”