A billboard for American Sniper has been taken down after it was graffitied with the word 'murder'.

The poster for Bradley Cooper's controversial Oscar-nominated film was defaced overnight in the Brentwood area of Los Angeles.

The movie has prompted intense debate in the US since it was released last week, with politicians and Hollywood stars wading in with their opinions.

Oscar-winning filmmaker Michael Moore initially criticised the movie for glorifying snipers, before later clarifying that there are aspects of it that he enjoyed.

Seth Rogen has also taken issue with the film, comparing it to the Nazi propaganda film-within-a-film in Inglourious Basterds.

However, Sarah Palin has defended the film and thanked producers Cooper and Clint Eastwood for "respecting the United States military".

Cooper has earned an Oscar nomination for portraying Chris Kyle, the deadliest sniper in US military history. Overall, the film is nominated for six Academy Awards.