Godsmack frontman Sully Erna criticised security guards at the band's gig in Pennsylvania last week after they used "unnecessary" force to haul a fan off the stage.

The band was playing in Pittsburgh on Aug. 31as part of the Rockstar Energy Drink Uproar Festival when a shirtless man jumped up on the stage and ran around before attempting to place a hat on Erna's head.

Members of the event's security team quickly tackled the fan, prompting Erna to stop singing and scold them for using rough tactics.

In video footage of the incident, Erna is heard telling the bodyguards, "Way f**king unnecessary, guys... Put him down. Seriously, that's crazy. The kid put a hat on me. It's OK. I don't need a f**king medic. Let him go back and enjoy the show. It's called f**king rock 'n' roll."

The singer then continued with the set.