WASHINGTON — The Justice Department said it is investigating five major TV broadcast networks for potentially violating federal antitrust laws after the networks temporarily declined to provide pool coverage of President Donald Trump, a department spokesperson said.

The investigation into the networks that make up the White House TV press pool — NBC, ABC, CBS, CNN and Fox News — is underway, and the department sent out “civil investigative demands” on Friday, according to a Justice Department official.

“Members of the television press pool have boycotted covering White House events. Group boycotts among commercial competitors can violate the Sherman Act. The Antitrust Division is simply investigating to determine whether these news organizations have violated the antitrust laws,” department spokeswoman Emily Covington said Saturday.

The pool is a rotating group of networks that share duties of recording the president’s activities during public appearances and travel. The network performing pool duty then distributes information and media, such as video footage and audio, to other outlets.

The New York Times first reported the investigation.

The White House did not immediately respond to a request for comment.

ABC News said it has not received any notification from the Justice Department but expects to. Representatives for NBC, CBS and CNN declined to comment. Fox did not immediately respond to a request for comment.

The investigation appears to be the latest move from the White House in its escalating feud against the press corps.

Last month, Trump barred CNN, MS Now and Politico from the White House grounds, citing what he said was “their constant ‘reporting’ FAKE NEWS!” The other networks in the TV pool briefly declined to participate in pool duties after CNN was removed from its spot in the rotation.

CNN, MS Now and Politico sued against the ban, claiming it was a violation of the First Amendment. They were reinstated about a week later after a judge ruled that the administration had to temporarily restore their access for 14 days. A federal judge this week extended the order to Tuesday.

The five major networks released a joint statement at the time, saying, “The public has a vital interest in receiving accurate, independent information about its government. No administration should restrict a news organization because it objects to its reporting.”

The pool system has been recognized by administrations from both parties for decades, and the coverage is used by pool members and subscribers, which includes outlets like Newsmax, One America News Network, C-SPAN and international outlets.

During the time the outlets declined to provide pool coverage, individual TV networks, including NBC News, continued to provide coverage of White House events that were open to the press, outside of the pool.

Bruce D. Brown, president of the Reporters Committee for Freedom of the Press, said in a statement that the First Amendment protects the decisions news organizations make about coverage, and called the investigation “another and even more brazen attempt to try to intimidate journalists.”

Kelly O’Donnell reported from Washington, and Marlene Lenthang from Los Angeles.