10/29/2012 01:17 EDT | Updated 12/29/2012 05:12 EST

Green Day cancels fall concerts, postpones tour start

Green Day is cancelling this fall's performances and postponing the start of its upcoming tour, as frontman Billie Joe Armstrong continues treatment for substance abuse.

Along with cancelling the club tour slated for this fall, the band announced Monday that it has postponed the beginning of its tour in the new year.

Green Day had been scheduled to launch a club tour in Seattle in late September and continue with dates through Dec. 10. Just days before the start, however, the band announced it was postponing the engagements.

The announcement came in the wake of Armstrong's angry public outburst at the iHeartRadio Festival in Las Vegas. Shortly after that incident, the band announced he was seeking substance abuse treatment.

Now, the remaining dates on the fall club tour have been cancelled, along with all scheduled appearances for January and February 2013. This includes concerts in Quebec City and Toronto, along with many U.S. stops.

"Obviously the timing for this isn’t ideal, but Billie Joe's well-being is our main concern," said Mike Dirnt, bass player for the Grammy-winning rock trio.

The band did, however, announce it is moving up the debut of Tre — the final instalment of its three-album release, following on the albums Uno and Dos — to Dec. 11, more than a month ahead of schedule.

"We feel bad we have to delay our tour, so to make up for it we want to give our fans the music earlier than we had planned,” according to drummer Tré Cool.

"If we couldn't be there to play it for you live, the least we could do was give you the next best thing."

The new album trilogy marks the group's first release of new material since 2009's 21st Century Breakdown. The punk rock trio is best known for albums such as Dookie, Insomniac, Nimrod and American Idiot, a rock opera that topped the music charts, won Grammys and other industry accolades, and also inspired a hit Broadway musical of the same name.