Story highlights Unclear when plan would be presented to Congress

Republican lawmakers have vowed to block President Obama

(CNN) Defense Secretary Ash Carter said Thursday he is readying a plan for President Barack Obama that would house some remaining Guantanamo Bay detainees in a secure facility in the U.S.

"That plan will propose bringing those detainees to an appropriate, secure location in the United States," Carter said. "While we work with Congress on a way forward, we will continue to transfer Guantanamo detainees to other countries when and as we have mitigated the risk to the United States."

A senior administration official said the plan does not include naming a specific site for relocation but rather includes a list of potential locations.

The possibilities are understood to include the federal Supermax prison in Florence, Colorado; the military prison in Leavenworth, Kansas; and the Naval Consolidated Brig in Charleston, South Carolina.

The official said Obama is in the "final stages" of reviewing the plan.

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