A federal judge has ordered the Trump administration to immediately reinstate access to the White House for three news organisations barred from the building last week by the president.

CNN, MS NOW and Politico must have their access restored for 14 days, the judge ruled, saying the ban “likely violated their constitutional due process rights”. Some reporters from the outlets said they were turned away on Thursday morning.

The three outlets launched a legal challenge after their reporters were denied access last weekend.

The administration had defended the move in court, accusing the outlets of publishing false information and threatening national security.

It was unclear whether all reporters from the outlets would be readmitted to the White House early on Thursday morning. CNN said some of their reporters had been denied, and others allowed in. MS Now said a reporter was also stopped from entering and a Politico reporter said they had been turned away.

The White House is yet to comment on the ruling, and lawyers acting for the president may take further legal action.

Judge Timothy Kelly ruled, external CNN, Politico and MS NOW were “likely to succeed” in showing the White House had not exercised “adequate due process” in implementing the ban.

He also cast doubt on the Trump administration’s arguments that the bans were motivated by national security concerns, pointing out the president made no mention of that in his initial announcement.

When President Donald Trump announced the ban on Friday, he accused the three news outlets of writing “fake news” and “fictions and lies” in their coverage of him and his team.

The ruling continued: “The record lacks factual support for Defendants’ contention that the revocation of Plaintiffs’ hard passes will in fact protect national security or that national security will be endangered if the Court orders their passes reinstated while this litigation proceeds.”

In its defence of the ban in a court filing on Tuesday, the Trump administration cited a number of articles published by the outlets, including some about construction at the White House, including work on a new ballroom.

The judge said that “in most cases” the stories the White House took issue with were written by journalists who “did not even hold card passes” – and in the remaining cases, the Trump administration did not demonstrate “reason to believe that the reporter’s possession of the hard pass was integral to the stories identified”.

In its original filing, the Trump administration cited declarations from defence department officials supporting the ban – but the judge said they had “no direct knowledge of how reporters operate in the White House, or about any of the facts at issue here”.

Ted Boutrous, the lawyer representing the news outlets, told CNN, external: “This is a strong ruling vindicating freedom of the press, due process and the rule of law.”

On Monday, major US TV networks pulled out of White House pool duties in protest at the ban. The arrangement sees media organisations share material with each other to save on costs and space when broadcasting presidential events to the American public.

Forty-nine media organisations – including CBS News, The New York Times and Fox News – also filed a legal brief in support of CNN, MS NOW and Politico’s lawsuit.

Trump frequently criticises news organisations, and his administration has launched legal action against a series of outlets, including the New York Times, the Wall Street Journal and the BBC.

Some of the lawsuits have resulted in media organisations agreeing to pay multi-million-dollar settlements. Trump’s lawsuit against the BBC is ongoing.