U.S. security boss clarifies comments about border

In a release Tuesday night following the interview, she called Canada a "close ally and an important partner" and said she was simply misunderstood. "I know that the September 11th hijackers did not come through Canada to the United States," she said in the statement. "There are other instances, however, when suspected terrorists have attempted to enter our country from Canada to the United States. Some of these are well-known to the public -- such as the Millennium Bomber -- while others are not due to security reasons."