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 US 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 US 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.