Fox News said Wednesday it would join rival CNN in its legal battle to restore the access of White House reporter Jim Acosta, maintaining that press credentials "should never be weaponized."
Fox, which has often been praised by U.S. President Donald Trump, said the revoking of the CNN reporter's press pass raises concerns over freedom of the press.
"Fox News supports CNN in its legal effort to regain its White House reporter's press credential," the news channel's president Jay Wallace said in a statement.
"We intend to file an amicus brief with the U.S. District Court. Secret Service passes for working White House journalists should never be weaponized. While we don't condone the growing antagonistic tone by both the president and the press at recent media avails, we do support a free press, access and open exchanges for the American people."
The announcement came a day after CNN -- part of the WarnerMedia division of AT&T -- said it was suing to restore the press pass of Acosta, barred after a testy exchange with Trump at a White House news conference.
Officials initially said the CNN chief White House reporter was banned for inappropriately touching a White House female intern as he struggled to hold on to a microphone and cited a video that appeared to have been manipulated.
Trump later said journalists might be barred if they were not "respectful."
Free speech activists said the case was important and that public officials should not be able to bar access to journalists if they dislike news coverage.
The White House dismissed CNN's complaint as "grandstanding" and vowed to "vigorously defend" against the lawsuit.
At least 10 other media outlets, including The Associated Press, Bloomberg, First Look Media, Gannett, NBC News, the New York Times, POLITICO, EW Scripps, USA Today Network, and the Washington Post - said they too would be filing amicus briefs in support of CNN.
"It is imperative that independent journalists have access to the President and his activities, and that journalists are not barred for arbitrary reasons. Our news organizations support the fundamental constitutional right to question this President, or any President," they wrote in a joint statement.
The White House initially sought to justify its action by saying Acosta placed "his hands on" an intern who was trying to take his microphone from him during last week's heated exchange with Trump. Sanders, the White House spokeswoman, then released what appears to be a doctored video to substantiate the claim.
She walked the assertion back in her response to CNN's suit that was filed Tuesday, saying Acosta "inappropriately refused to yield to other reporters" during last week's press conference.
"The White House cannot run an orderly and fair press conference when a reporter acts this way, which is neither appropriate nor professional," she said without repeating earlier allegations of inappropriate contact.