U2 just announced that Bono had to undergo emergency back surgery as the result of an injury resulting from prepping for the tour planned to start on June 3rd in Salt Lake City, so the start of the tour has already been postponed. From U2.com…

Following Bono’s unexpected back surgery earlier today, Live Nation confirmed that the U2 U2360° tour launch previously scheduled for June 3rd in Salt Lake City has been postponed.

U2 fans with tickets to the June 3rd event are encouraged to retain tickets until updated show information can be provided.

Additional tour information will be forthcoming.