American thrash metal band Megadeth cancelled a show in Paraguay Saturday after swarms of fans crashed through the security gates protecting the stage, in a stampede that left several injured.

It had already been a rowdy concert at the Sport Colombia stadium in Asuncion, where vendors were selling alcoholic beverages in glass bottles -- which some fans hurled onto the stage, according to witnesses.

It came to an abrupt end when hundreds of fans broke through the security barricade, crushing several people and leaving them injured, according to police.

Megadeth frontman Dave Mustaine announced on Twitter that the band had called off the show.

"Dear Paraguay, after all three barricades broke and hundreds of fans crushed three security guards, almost killing one female fan, we regretfully had to cancel the show," he wrote.

He also posted a picture of what he described as the inadequate security barrier.

"Barricade held by a string at Asuncion. Two crew hit by broken glass thrown by persons in audience. Disappointed."

He promised the band would return to Paraguay someday and use a different venue, security and promoter.