Rock music icon Chris Squire, who announced last month he was undergoing treatment for leukemia, has died, his Yes bandmates announced Sunday on Facebook.

"It's with the heaviest of hearts and unbearable sadness that we must inform you of the passing of our dear friend and Yes co-founder, Chris Squire," read the British band's post.

"Chris peacefully passed away last night in Phoenix Arizona. We will have more information for you soon."

"Utterly devastated beyond words to have to report the sad news of the passing of my dear friend, bandmate and inspiration Chris Squire," Geoffrey Downes tweeted.

Squire said in May he was taking a hiatus from the band -- of which he has been a member since 1969 -- while he underwent treatment for the disease.