The Department of Justice has opened an antitrust investigation into five major television networks for their brief suspension of pooled White House coverage last month.

The probe targets ABC, CBS, CNN, NBC and Fox News. It examines whether the networks' coordinated decision to halt shared coverage violated the Sherman Act by constituting an illegal group boycott among competitors.

A Justice Department spokesperson confirmed the inquiry Saturday. The statement noted that group boycotts among commercial competitors can violate antitrust laws and that the Antitrust Division is determining whether the news organizations broke federal rules.

The investigation stems from events in September. The White House revoked credentials for CNN, Politico and MS NOW on September 19. The networks responded by suspending the longstanding television pool arrangement, under which they rotate responsibility for filming presidential events and distributing footage.

Some presidential events, including a meeting with Chinese President Xi Jinping, received no pooled coverage during the brief halt. The networks resumed the pool after a federal judge issued a temporary restraining order restoring access.

Network representatives have not commented publicly on the probe. The DOJ first contacted the outlets Friday with document requests related to the pool's formation and recent operations.

The inquiry adds to ongoing tensions between the Trump administration and major media outlets. It follows public suggestions from Trump allies that the networks' actions warranted antitrust scrutiny.

The investigation remains in its early stages. It focuses on potential civil violations rather than criminal charges at this point.