TORONTO - Juno Award-winning post-hardcore rockers Alexisonfire are splitting up after two members decided to leave the group in a break-up that frontman George Pettit says is "not really" amicable.

The St. Catharines, Ont., band announced their decision in a lengthy note posted to their website, written by Pettit.

"After 10 years, Alexisonfire has decided to part ways," he wrote. "Was the break-up amicable? Not really. Was it necessary? Probably.

"Regardless, the members of this band are my family and I wish them nothing but good fortune."

The band issued its self-titled debut album in 2002, and followed up with 2004's platinum-selling breakthrough "Watch Out," a moody fusion of emo, metal and hardcore that won the group a passionate mass audience who identified with their searching, angst-ridden lyrics.

The group's third album -- 2006's "Crisis" -- opened in the top spot on the Canadian charts en route to platinum sales, while 09's "Old Crows/Young Cardinals" -- which could now stand as their final full-length -- opened at No. 2 and also sold briskly.

But as the band was gathering commercial and critical steam, singer/guitarist Dallas Green was winning just as much acclaim with his solo project, City and Colour.

Beginning with 2005's platinum-selling "Sometimes," Green's project -- which earned the tattooed crooner two Junos separate from his work in Alexisonfire -- also picked up momentum with each passing album.

His third album, "Little Hell," debuted at No. 1 on the Canadian charts when it was released in June and has reached as high as the 28th spot on the U.S. Billboard chart.

And Pettit said that Green privately revealed his intention to leave Alexisonfire almost a year ago due to the burgeoning success of City and Colour.

"Trying to balance his life between touring with us and at the same time quelling the success of City and Colour was a task too difficult to continue managing," Pettit wrote.

"He informed us he wanted to focus his efforts on City and Colour."

At that point, Pettit said, the band planned to soldier ahead by finding a replacement for Green. But then guitarist Wade MacNeil accepted an offer more recently to also depart Alexisonfire for another band, and at that point, the group decided to dissolve completely.

"Replacing one guitar player/singer/writer was something we thought was possible, but replacing two would run the serious risk of perverting the legacy of what we had achieved," Pettit said.

"So we all took a good hard swallow and decided to end it so it would never get old and ugly."

Pettit said that the future for him and drummer Jordan Hastings was "largely unwritten," but advised fans to listen out for upcoming projects.

He added that the band has talked about releasing projects relating to their 10th anniversary, and that a farewell tour through Canada had also been discussed.

He finished by offering heartfelt thanks to the band's notoriously devoted following.

"I would like to offer my sincerest gratitude to the fans of Alexisonfire around the world. I'm forever grateful to anyone who has ever taken any interest in what we did. You were the coal that stoked our engines. You have given us a spectacular decade, rich with experience and joy. I love you all.

"Take solace in the fact that you live in one of the most exciting musical eras. Try to support some of your local independent artists the same way that you supported us. A life of musical exploration is a rich and fulfilling one."