"Bowling for Columbine" director Michael Moore says he's saddened that the nation has not made enough strides toward ending violence in schools.
His 2002 documentary, which won an Academy Award, was inspired by the 1999 Columbine High School shootings in Colorado.
Last month, 20 children and six adults were shot to death at an elementary school in Newtown, Connecticut.
Speaking before the National Board of Review Awards on Tuesday night in New York City, Moore said it's "personally heartbreaking" to think his pro-gun control film had little impact.
He also said Americans were "a violent people" and the nation needed to take a closer look at itself.