A U.S.-backed Syrian coalition has announced a campaign to reclaim Raqqa, the unofficial capital for ISIS.
The Syria Democratic Forces announced the campaign on Sunday, three weeks after U.S.-backed Iraqi forces launched an effort to retake Mosul.
U.S. Defense Secretary Ash Carter said he welcomed the announcement.
"The effort to isolate, and ultimately liberate, Raqqa marks the next step in our coalition campaign plan," Carter said in a statement. "As in Mosul, the fight will not be easy and there is hard work ahead, but it is necessary to end the fiction of ISIL's caliphate and disrupt the group's ability to carry out terror attacks against the United States, our allies and our partners. The international coalition will continue to do what we can to enable local forces in both Iraq and Syria to deliver ISIL the lasting defeat it deserves."
The offensive on Raqqa ramps up pressure on ISIS as the group defends Mosul as well, Reuters reports. The U.S. will coordinate air strikes with the Syria Democratic Forces, which includes the Kurdish YPG militia.