Sen. Mark Kirk has apologized for a comment he made Thursday during a debate with challenger Tammy Duckworth that was met with "thunderous condemnation" around the country, NBC Chicago reports. "I forgot that your parents came all the way from Thailand to serve George Washington," the Hill quotes the Illinois Republican as saying during the debate. The congresswoman's mother immigrated from Thailand, but her father—an American WWII veteran—traces his family's military service back to the Revolutionary War. Duckworth herself lost both legs while serving in Iraq. "Sincere apologies to an American hero, Tammy Duckworth, and gratitude for her family's service," Kirk tweeted Friday. His campaign also issued a statement: "Sen. Kirk has consistently called Rep. Duckworth a war hero and honors her family’s service to this country." (More Mark Kirk stories.)