The U.S. Bureau of Indian Affairs has ordered the Cherokee Nation to restore voting rights and benefits that were revoked from about 2,800 descendants of slaves once owned by Cherokee members, known as freedmen.

In August, the Cherokee Nation Supreme Court reversed and vacated a district court decision that granted equal tribal citizenship rights to descendants of freedmen and immediately stripped them of their voting rights and benefits including medical care, food stipends and assistance for low-income homeowners.

"I urge you to consider carefully the nation’s next steps in proceeding with an election that does not comply with federal law," Assistant Secretary for Indian Affairs Larry Echo Hawk wrote in letter Friday to acting Chief S. Joe Crittenden. "The department will not recognize any action taken by the nation that is inconsistent with these principles and does not accord its freedmen members full rights of citizenship."

The Associated Press provides more context and recent history of the Cherokee Nation and freedmen:

The tribe also barred the descendants from voting in a Sept. 24 special election for principal chief. The Cherokee Supreme Court ordered the special election after it said it could not determine with certainty the outcome of a close and hotly contested June election between incumbent Chad Smith and longtime tribal councilman Bill John Baker. The results had flip-flopped between the two during weeks of counts and recounts. Baker had twice been declared winner, but so had Smith. … More than 76 percent of Cherokee voters approved a 2007 amendment removing the freedmen and other non-Indians from the tribal rolls, but no action was taken until the tribe’s Supreme Court upheld the results of that special election last month. Cherokee leaders who backed the amendment, including Smith, said the vote was about the fundamental right of every government to determine its citizens, not about racial exclusion.

The U.S. government says a 1866 treaty between the Cherokee tribe and the U.S. government guaranteed that the slaves were tribal citizens, whether or not they had Cherokee blood.

"The Cherokee Nation will not be governed by the U.S. Bureau of Indian Affairs," Joe Crittenden, the tribe’s acting principal chief, said in a statement. "We will hold our election and continue our long legacy of responsible self-governance."

The federal government, however, says that unless the freedmen are allowed to vote in the election on September 24, the results will not be valid. The U.S. Department of Housing and Urban Development is also withholding a $33 million disbursement until the Cherokee Nation accepts the freedmen.