Dozens of fans walked out of a Pearl Jam concert in Denver after lead singer Eddie Vedder took a mask of US President Bush and impaled it on a microphone stand.

Members of the audience booed and shouted for Vedder to shut up as he told the crowd he was against the war and Bush.

Vedder impaled the mask during the encore of the band's opening show of a US tour.

Vedder used a the Bush mask previously in Australia and Japan to perform the song 'Bushleaguer' from the band's latest album, 'Riot Act', The song's lyrics say, "He's not a leader, he's a Texas leaguer."

During the show, Vedder said, "Just to clarify... we support the troops. We're just confused on how wanting to bring them back safely all of a sudden becomes non-support."