Iraqi authorities have revoked the operating licence and closed the Baghdad offices of the media network Al Jazeera.
Founded by Qatar's ruling family in 1996, Al Jazeera aggressively covered the Arab spring uprisings and has broadcast extensively on the civil war in Syria.
In 2013, Iraq's government accused Al Jazeera of fostering sectarian sentiment that was fuelling violence. Iraq is now accusing Al Jazeera of violating government guidelines issued in 2014 to regulate media "during the war on terror".
Al Jazeera said it was dismayed by the action. "We remain committed to broadcasting news on Iraq to Iraqi people, our viewers in the Arab world and across the world," the channel said.
Rights groups have criticised Iraq's media guidelines, which restrict journalists from covering insurgent movements and require them to report in favourable terms on government forces.
Qatar itself is a harsh critic of the Syrian regime and a leading backer of the rebels, and has been accused by many supporters of Iraq's government of backing dissent in Iraq.