Experimental Icelandic quartet Sigur Ros has backed out of six European festival appearances in order to finish work on its next MCA studio album.

Experimental Icelandic quartet Sigur Ros has backed out of six European festival appearances in order to finish work on its next MCA studio album. "We're not in the habit of canceling shows, but unfortunately the album is taking longer than we expected and we have to finish it in order for an autumn release," wrote bassist George Holm on the band's official Web site. "We should be back around the release date, and we hope to see you then."

The shows were due to begin July 28 at the Galway Arts Festival in Ireland. Sigur Ros will still make appearances Aug. 17-18 at the V2002 festival in Chelmsford and Staffordshire, England. In the meantime, work will continue on the as-yet-untitled follow-up to the acclaimed "Agaetis Byrjun," which peaked at No. 24 on Billboard's Top Independent Albums chart in January and won the inaugural U.S. Shortlist Prize.

Live clips of such new tracks as "Popplagid" and "Daudalagid" are available to download via the band's Web site. Comparing the new songs to "Agaetis Byrjun," frontman Jonsi Thor Birgisson recently said, "the main difference is that this time the production will be less polished. The sound will be much more bare and alive. And far fewer little slick things and much less sweet stuff. I think playing the songs a lot at concerts and then recording them hasn't been a very thrilling experience for us. I think next time we'll record the songs as we make them [to] try to keep them fresh for us."

Here are Sigur Ros' canceled tour dates:

July 28: Galway, Ireland (Galway Arts Festival)
Aug. 1: Odemira, Portugal (Sudoeste Festival)
Aug. 3: Valencia, Spain (Benicassim Festival)
Aug. 8: Jena, Germany (Kulturarena Festival)
Aug. 9: Haldern, Germany (Haldern Festival)
Aug. 11: Saint-Malo, France (La Route du Rock Festival)