Irish rock band U2 was forced to postpone a concert in Stockholm, Sweden on Sunday night when the arena was evacuated due to a gunman threat.

Fans, who had already packed into Swedish concert venue the Globen, were asked to leave the area “due to a security breach” just before the band was set to come on stage.

"As the breach has not been resolved quickly and as audience safety is paramount, the police have advised The Globen and Live Nation that they have no option but to postpone tonight's show," the band wrote on their website.

The band have not confirmed the exact nature of the security breach, although it is reported in the Irish Mirror that police were searching the crowds for a man in his 20s armed with a gun who had threatened a member of the audience. Helicopters were also used to search the scene.

The show was postponed to this evening, Tuesday, September 22, and the organizers have apologized to fans for the short notice in canceling the event.

"All tickets from Sunday 20th September are valid for Tuesday 22nd September. The organizers apologize for the inconvenience caused and thank the audience for their understanding. Their safety is the priority," they said.

This is the latest in a string of unfortunate incidents the band has experienced during their iNNOCENCE + eXPERIENCE international tour which began in May.

On opening night, guitarist The Edge fell off the stage and just a few weeks into the tour the band’s long-time tour manager Dennis Sheehan was found dead in his hotel room in Los Angeles.

The tour also hit a serious setback before it had even started when front-man Bono sustained serious injuries in a bicycle accident in New York in November 2014.

Fans in Ireland have been hit with problems with their credit card purchases also. Bank of Ireland customers have been advised to destroy the creidt cards with which they made the original purchase.

Bank of Ireland is rolling out new Mastercard credit cards to replace their Visa cards and customers have been told to destroy the old cards.

For those who made credit card purchases of “paperless tickets” for Dublin dates, the physical card needs to be shown to gain admission. All those who bought “paperless tickets” have been advised to contact Ticketmaster to ensure that they will gain access to the concert.

H/T: Irish Mirror

Police search for an armed man in his 20s who threatened a member of the audience.John Athayde/Flickr