On three occasions vocalist Fred Durst interrupted the band’s set to draw attention to the plight of fans being crushed at the front of the 30,000 crowd and spoke of the lack of barriers.

“Great show in Warsaw, but the people getting crushed and passing out didn’t need to happen,” guitarist Wes Borland wrote on Twitter. “Festivals should always use T barricades.”

Krzysztof Dabrowski, Ursynalia Students Festival’s promoter and head of production, hadn’t responded to a request for comment at press time.

It’s the second time in a year that a headline act has had problems with a Polish festival over the failure to provide barriers.

Last August, a potentially life-threatening crowd crush was narrowly avoided during a Prodigy show at Przystanek Woodstock, considered to be Europe’s biggest free festival.

The act’s production team said there weren’t enough barriers for an event that claims to have had at least 500,000 on site.

The festival says the pit barrier it provided at Prodigy’s insistence was the cause of the crowd crush, which left up to 100 fans injured.

Festival organiser Jurek Owsiak went on Polish TV complaining the act ruined the event because of its demands, while Prodigy manager John Fairs said Przystanek was “the most unsafe festival” he’s seen in 25 years.

Other acts on the Ursynalia bill June 1-3 included Slayer, Billy Talent, Nightwish, In Flames, and Mastodon.