Sean Penn

Actor Sean Penn issued a warning to Barack Obama that he may have to become a greater man than he has ever been or face "dangerous disillusionment".

Penn, jury president of the 61st Cannes Film Festival, was speaking at a press conference, along with other members of the panel.

Penn also spoke out about "inane stupidity" when talking about US President George Bush's politics.

Penn continued: "When somebody operates without a brain and without a heart they kill hundreds of thousands of people throughout the world.

"It is a shame that we have to bastardise the word 'politics'..."

Penn said he was not supporting a particular US Presidential candidate, but was "encouraged and excited" by the support Obama had received.

He said: "I hope that he will understand if he is the nominee the dangerous disillusionment that will happen if he does not become a greater man than he's ever been."

He said failure to do so may be a "death knell" adding: "This is the most important election in my lifetime and maybe ever."

Fellow jury member Natalie Portman said she was not endorsing anyone.

She continued that it was a very exciting year for American politics, "that for the first time in a while we have to chose between who we like better instead of who we hate less".