Bono remains in hospital today after undergoing emergency surgery in Germany.
The U2 frontman is under the care of neurosurgeons at a Munich hospital after the emergency operation on his back.
The exact nature of the injury has not been disclosed so far, but a number of reports today said that Bono had undergone spinal surgery.
The singer was hurt while training for the US leg of U2's 360 Degree world tour, due to kick off next month.
He was rushed to the neuro-surgery unit of a Munich hospital where he remains under the care of specialist Prof Jorg Tonn and Dr Muller Wohlfahrt.
The singer is to remain in hospital for the next few days.
Bono, who celebrated his 50th birthday in New York earlier this month, sustained the injury during "tour preparation training".
A statement said that he will spend the next few days there, "before returning home to recuperate".
Once his condition has been assessed further, a statement will be made regarding the impact on the band's forthcoming tour dates.
The band's first date of their 360 tour this year in Salt Lake City has now been postponed.
The are due to tour the US, Europe and Russia through this year in the latest leg of the tour which came to Croke Park in Dublin last year. U2's manager, Paul McGuinness, posted a message to fans on the band's website saying: "The band were really looking forward to getting back out on the road until the emergency surgery on Bono's back which took place in Munich.
"We were due to start rehearsals on Tuesday in Salt Lake City and get the show ready for the next leg. There were going to be some changes, and some new material.
"It is unfortunate we're inconveniencing fans. We will make plans to reinstate these dates as soon as possible.
"Obviously it's been very disruptive for our crew as well. We have over 400 people converging on Salt Lake City and some of those have been turned around and told to stay at home until we make our new plan."
Fans due to attend the Salt Lake City gig on June 3 have been encouraged to retain their tickets and await information.