Asked by NBC News whether the offensive would start within weeks, Carter replied “that is our plan,” adding the operation was planned to follow the beginning of the assault on Mosul in Iraq.
He ruled out that US special operations troops in Iraq could be a part of occupation forces.
Carter is in Paris where he has been meeting with Western colleagues. He admitted on Tuesday that the Pentagon was already working with its allies on a plan to isolate Raqqa.
Last week, US Joint Chiefs of Staff Chairman Gen. Joseph Dunford said the Department of Defense expected a victory in Mosul and Raqqa in the coming months.
The Daesh terror group, outlawed in Russia, took full control of Raqqa in 2014 and declared it the capital of their “caliphate.” Earlier this month, the Iraqi government launched an offensive to seize the Daesh stronghold of Mosul with air cover from the US-led coalition.