Mel Gibson has criticised the Iraq war while promoting his new film Apocalypto.

The actor took the opportunity to compare the decision to invade with the subject of his film - the collapse of the Mayan civilization.

Gibson, a Christian thought of as a right-winger politically, appeared unexpectedly at the Fantastic Fest film festival in Austin, Texas. He took questions at the public event just a month after admitting drunk driving and apologising for making anti-Semitic remarks.

"The precursors to a civilization that's going under are the same, time and time again," he said after a screening of the movie, according to the Hollywood Reporter. "What's human sacrifice if not sending guys off to Iraq for no reason?"