A federal judge has ordered US President Donald Trump to restore White House access for journalists from CNN, MS NOW and Politico, saying his ban on the three media outlets was likely unconstitutional.

US District Judge Tim Kelly issued his order in a lawsuit that the news organisations filed contesting the ban, which the Republican president announced on September 18.

Mr Trump had said on social media that the three outlets "shouldn't be able to constantly write or report FICTION and LIES", and Justice Department lawyers had sought to justify the ban on national security grounds.

All three news outlets said their teams' press passes were confiscated on Saturday morning, local time, when their reporters went to the White House.

The US president has developed a hostile relationship with journalists and media outlets who report critically on his administration, during his two terms in office.

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