Hollywood star Sean Penn said on Saturday that he is happy to be a "propagandist" for the Ukrainian war efforts, as he called Russian President Vladimir Putin a "creepy little bully" in Berlin.

He made the remarks after the world premiere of his documentary 'Superpower', which is about Ukraine President Volodymyr Zelensky, reports 'Variety'.

"This is not an unbiased film because this is not an ambiguous war," he said, calling the conflict "extremely personal".

"I'm very happy to be considered a propagandist. I was happy to make an unbiased film because that is the true story we found," the 'Dead Man Walking' star said.

As per 'Variety', donning a black jacket and a hoodie and sporting a camouflage trucker cap, Penn repeatedly called on the Joe Biden administration to send precision, long-range missiles to Kiev to support the Ukrainian war effort.

Praising the courage of Zelensky, Penn lashed out at his Russian counterpart when asked if the filmmakers wanted to hear from Putin, whom he described as a "war criminal".

"It was quite clear to us that we were not going to allow our film to be a podium for transparent deception. I think we would have been better served talking to a wall," he said.

'Superpower', which Penn co-directed with Aaron Kaufman and is produced by Vice, met with a standing ovation on Friday night in Berlin, after its premiere out of competition as a Berlinale Special Gala.