U2 were set to perform in Stockholm, Sweden yesterday, September 20, at The Globe but were forced to cancel and postpone the show due to a “security threat.”

As to what that threat was specifically, several reports offer conflicting answers. No official statement has been made as to the actual “risk” but rumors of a bomb threat were initially prominent. Some sites are reporting that police were in search of a gunman who was allegedly in the venue.

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A statement on the band's official website offered the following:

Due to a security breach, Stockholm's The Globen evacuated the audience from the building this evening.

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, to a rescheduled date of Tuesday 22nd September.

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.”