There's Yankees, and then there's damned Yankees...

James Montgomery was authorized to raise a regiment of African-American infantry in January 1863 that would become the 2nd South Carolina (African Descent).

Montgomery led a raid on the coastal town of Darien, Georgia, which he ordered looted and burned even though it was not defended and had not offered any resistance. 

Colonel Robert Gould Shaw condemned the action, and in a private letter gave Montgomery's reason for burning the town as "that the Southerners must be made to feel that this was a real war, and that they were to be swept away by the hand of God, like the Jews of old."

Montgomery stated to Shaw, "We are outlawed, and therefore not bound by the rules of regular warfare."