Rodrigo Duterte’s government moved on Monday to strip ABS-CBN, the Philippines’ largest media group, of its franchise. The move has been criticized as the worst yet in a series of attacks on press freedom by the country’s government.

Jose Calida, the Philippine solicitor general, filed a complaint accusing ABS-CBN Corp. and a subsidiary of violating a constitutional restriction on foreign ownership of mass media by allowing foreign investors to join the company. The country’s House of Representatives is currently set to deliberate over bills supporting the renewal of MBS-CBN’s franchise, and it is unclear how this will be affected by the government action.

Critics have characterized the move as the latest in a series of attacks on press outlets critical of the Duterte government. In 2018 the government advanced a similar constitutional complaint against online news site Rappler, which, along with ABS-CBN, has reported critically about Duterte’s deadly antidrug campaign. The site had its license revoked in a decision that is under appeal.

Protesters gathered near the ABS-CBN headquarters at a rally led by the National Union of Jounalists of the Philippines (NUJP) on Monday afternoon. NUJP chairman Nonoy Espina said that the petition could open the door to similar attacks against the press if it is successful.