Legendary singer-songwriter Cat Stevens, also known as Yusuf, announced that his upcoming North American book tour will be postponed due to unspecified visa issues.

The “Morning Has Broken” singer took to Instagram to share the news on Monday, saying his “Cat on the Road to Findout” book tour won’t be going ahead as scheduled next month. The book will be released in the U.S. on Oct. 7 and was made available in the U.K. earlier this month.

“Waiting months for visa approvals, we held out as long as we could,” he wrote. “However, at this point, the production logistics necessary for my show cannot be arranged in time.”

He added: “I am really upset! Not least for my fans who have bought tickets and made travel plans to see me perform.”

Stevens said North American fans may still get a chance to see the tour “if visa approvals come through,” though he said those dates would most likely be “some time away” because of other commitments.

“Hopefully, fans will be able to hop on the Peace Train route at some time in the future,” he added. “Meanwhile, tour delays should not affect the book, which you’ll still be able to enjoy… the obvious benefit of it being — books don’t need visas!”

The singer-songwriter, who changed his name to Yusuf Islam after embracing the Muslim faith, did not specify any reason for the visa delays. He is the latest in a string of international musicians and athletes impacted by visa issues, as fees have increased in the past year and processing times have slowed.

Representatives of Stevens did not immediately respond to The Associated Press’ request for comment.

The singer’s tour was set to start Oct. 2 in Philadelphia and had various stops scheduled across the country for the rest of the month. His Oct. 8 tour stop in Toronto, Canada, was also postponed.

The British singer-songwriter rose to fame in the 1960s and put his career on hold for two decades after converting to Islam in the late 1970s. He returned to secular music in the 2000s.