Metallica drummer Lars Ulrich has raised doubts about how long the band can continue to perform at such a high level.

The American metal band are due to head out on a three month US tour next month following a small run of preview shows for their new album, 'Death Magnetic'.

Despite his praise for the other elder statesmen of the music industry, including Rolling Stones drummer Charlie Watts, Ulrich highlighted how none have to play songs at Metallica's tempo.

"The Rolling Stones, Black Sabbath, Aerosmith, I have nothing but respect for their longevity but (Stones drummer) Charlie Watts isn't playing 'Damage, Inc.' three times a week or playing 'Whiplash' every night,” he told Rolling Stone.

"This (Metallica) has the potential to go on for a long time. But if somebody's arm, back or neck just says, 'Fuck this,' and quits, I don't know..."

(by Jason Gregory)