Having finished the Vertigo world tour, U2 singer Bono has spoken of his desire to reinvent the band's sound for their next album.

Billboard reports that in an interview with Jo Whiley on BBC Radio One, Bono said: "Our band has certainly reached the end of where we've been at for the last couple of albums. I want to see what else we can do with it, take it to the next level; I think that's what we've got to do."

He continued: "We're gonna continue to be a band, but maybe the rock will have to go; maybe the rock has to get a lot harder. But whatever it is, it's not gonna stay where it is."

The singer also spoke of his interest in exploring songs that would just feature acoustic guitar and vocals.

"I would like to do a couple of tunes in that direction, with just a lot of space around the voice," he said. "I'd like to strip things down; that's something I'd be very interested in at the moment."

U2 are due to go into the studio shortly with the plan to release their new album before the end of the year.