The U2 front-man Bono underwent emergency back surgery after sustaining a bad back injury during the band's rehearsals in Germany for their upcoming '360 Degree' world tour.

A statement released from the bands spokesperson said that Bono "will spend the next few days in a Munich hospital before returning home to recuperate."

"Once his condition has been assessed further, a statement will be made regarding the impact on forthcoming tour dates," the spokesperson said.

The statement said that Bono was treated for an "injury sustained during tour preparation training."

However no elaboration was given as to what kind of injury the superstar sustained while in rehearsal.

U2 are only weeks away from their June 3 kick off US tour in Salt Lake City.

It is unclear if Bono will be fit enough to perform then.

This is a continuation of the band's 2009 U2 360 tour, which grossed just shy of $110 million, making it the year's most profitable show, according to Billboard magazine.

Bono is being treated at a specialist Nero surgery unit and is expected to make a full recovery.

U2's June 3 concert at Rice-Eccles Stadium has been postponed.

The band's website said that Bono will be having emergency back surgery, delaying the start of the "U2 360" tour, which was to have begun its next leg in Salt Lake City.

Bono suffers serious back injury