U2 lead singer Bono had emergency surgery on his back in a Munich hospital on Friday (May 21) after being injured while preparing for the next leg of a world tour, the first date of which has been postponed.
The 50-year-old from Ireland had been getting ready for the North American leg of the "360 Degree" world tour which had been due to kick off in Salt Lake City on June 3, according to a statement first released to Reuters.
Any lengthy disruption would be a blow both to fans and to Live Nation, the concert company which has a major deal to handle U2's merchandising, digital and branding rights as well as touring.
The band's website confirmed that Salt Lake City had been postponed.
Paul McGuinness, the group's longstanding manager, hinted that the injury could cause further postponements.
"It's unfortunate that we're inconveniencing fans," he said in an audio message. "We will make plans to reinstate these dates as soon as possible.
"Obviously, it's been very disruptive to our crew. We have over 400 people converging on Salt Lake City. Some of those have been told to turn around and told to stay at home until we make our new plan."
A spokesperson for Bono said the singer was admitted to a specialist neuro surgery unit in a Munich hospital.
"Bono will spend the next few days there, before returning home to recuperate," the spokesperson added. "Once his condition has been assessed further, a statement will be made regarding the impact on forthcoming tour dates."
After Salt Lake City U2 are scheduled to play in Anaheim on June 6 and 7 followed by Denver on June 12 and Oakland on June 16.
The 2009 tour helped the band earn around $109 million, based on Billboard figures. The U2 360 Tour, so-called because fans surround a giant circular platform, has been predicted to become the highest-grossing tour in history.