Dozens of people at a Michigan rally released balloons Saturday to mark the four-year anniversary of Iran's refusal to free a former Marine from prison.

But they first heard from Amir Hekmati, whose words were recorded weeks ago during a phone call with relatives. He has been in an Iranian prison since 2011, although the U.S. government denies he's a spy and has repeatedly called for his release.

"The list of people I want to thank is far too long to include here," Hekmati, 32, said.

Rain suddenly stopped in Bay City as about 100 people turned out to hear remarks from Hekmati's Flint-area family, U.S. Rep. Dan Kildee, D-Michigan, and others, including a Detroit-area imam who said he visited Hekmati in prison on Aug. 18.

Mohammad Ali Elahi predicted that Hekmati could be released soon.

"It was a miracle that I was able to meet with him," Elahi told The Bay City Times. "He was very strong spiritually and psychologically, and very relaxed."

Kildee said he hopes there won't be a fifth-anniversary rally next year.

"We're closer now than we ever have been, but until we see him, we can't stop. We can't stop this fight," Kildee said.

Sarah Hekmati spoke to her brother by phone before the rally and said he's humbled by the support. It's a tough time for the family: Their father, Ali, was treated for brain cancer and has suffered two strokes since Amir was arrested.

Sarah Hekmati, 34, was in Vienna to meet with Iranian representatives during U.S.-Iran nuclear talks earlier this summer.

"For the most part they were receptive," she told The Associated Press. "We brought letters from our father's physicians to appeal to them. ... My father's health is deteriorating."