English progressive rock act Yes has canceled its upcoming 26-city North American amphitheater and area tour, citing its founding vocalist Jon Anderson's recent health problems.

"In the wake of my recent respiratory attack, doctors have advised me to spend the coming months resting and recovering," Anderson said in a statement. "I'd like everyone know how deeply disappointed I am by this turn of events."

Anderson was admitted to a hospital last month after suffering from an asthma attack. Doctors have diagnosed the singer with acute respiratory failure, and have suggested he rest for at least six months.

Ticket refunds will be available at point of purchase. It was unclear at deadline if Yes would reschedule the tour.

The Live Nation-produced trek, which was to celebrate Yes' 40th anniversary, was scheduled to begin July 12 at Canada's Quebec City Festival, and wrap Aug. 22 in Los Angeles. The band was also expected to release a live album in conjunction with the canceled tour.