Cat Stevens, who also goes by Yusuf, has postponed the North American leg of his book tour due to unspecified visa issues, the singer announced on social media Monday.

The Rock & Roll Hall of Fame member was set to tour in support of his book, “Cat on the Road to Findout,” which will release in the U.S. on Oct. 7 and was made available in the U.K. earlier this month. The book release won’t be impacted, Stevens wrote, noting that “books don’t need visas!”

Stevens 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.

Stevens wrote that his team waited months for visa approvals, but “at this point, the production logistics necessary for my show cannot be arranged in time.”

“I am really upset!” Stevens wrote on social media. “Not least for my fans who have bought tickets and made travel plans to see me perform.”

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 and had a six-city concert tour in North America in 2014.

Stevens indicated the tour could be rescheduled if visas are approved, but those dates “would be some time away because of other travel fans,” he wrote.

The tour, announced in May, was described as a “portal” into the singer’s universe, offering an in-depth conversation on the memoir and acoustic performances of select songs, according to the website. Stevens began the tour visiting several cities in the U.K. throughout September.

Stevens wrote “hopefully, fans will be able to hop on the Peace Train route at some time in the future.”