GANGNAM Style rapper Psy has apologised for protesting against America's military presence in his home country, South Korea.

Psy, whose hit has had more than 909 million views on YouTube, smashed a model of a US tank at a concert in 2002 and performed a song at a gig in 2004 that apparently described killing "Yankees" who tortured Iraqi prisoners.

The singer, who is due to perform in front of Barack Obama at the annual Christmas in Washington TV special, said he would "forever be sorry" for any pain he had caused.