Korean rapper and YouTube sensation PSY has issued an apology to Americans after reports surfaced that he had performed anti-American songs on stage several years ago. The "Gangnam Style" rapper got in on anti-war protests in the early 2000s, apparently even performing a song which talks about killing "Yankees" and their families, "slowly and painfully."

"While I'm grateful for the freedom to express one's self, I've learned there are limits to what language is appropriate and I'm deeply sorry for how these lyrics could be interpreted," wrote PSY in a statement. "I will forever be sorry for any pain I have caused by those words."

The South Korean explained that his out-of-line reaction to the war was enflamed by the death of two Korean school girls, who were accidentally killed by a U.S. military as they walked alongside the road.

Despite the recent news, President Obama still intends to enjoy the "Christmas In Washington" concert which features PSY as a performer. The concert will be aired December 21 on TNT.

Source: huffingtonpost.com