A number of prominent Muslim figures in the U.S. have called on Iran’s Supreme Leader to release Shane Bauer and Joshua Fattal, the two Americans detained in Iran since summer of 2009.

Mohammad Ali Clay, the three-time World Heavyweight Champion, was among 13 Muslim figures who together with the families of the two American detainees have written to Ayatollah Khamenei urging him to show “Islamic compassion” toward Bauer and Fattal.

They write: “We are certain that your tender Islamic compassion will result in a more positive image of Islam and will assist researchers and Islamic organizations to create a credible community in the United States.”

Mohammad Ali Clay had also called on Ayatollah Khamenei to release the American detainees in a letter last year.

He was present at the press conference but due to his ailments, his wife spoke on his behalf.

Iranian authorities arrested Sharah Shourd, Josh Fattal and Shane Bauer in the border regions of Iran and Iraq in the summer of 2009.

While the three U.S. citizens claim they were hiking in the region and had inadvertently strayed into Iranian territory, Iran has charged them with illegal entry and espionage.

Last September, Iran agreed to release Sarah Shourd on $50,000 bail and allow her to return to the U.S. on humanitarian grounds.

She is now being summoned back by the Iranian judiciary to stand trial, and her absence has caused delays in the trial of the other two detainees.

Ramin Mehmanparast, the spokesman for Iran’s foreign ministry, rejected the possibility that the U.S. detainees were mere hikers, and said: “How can some Americans come to the borders of Iran and Iraq for their weekend getaway and engage in hiking in such sensitive territory? Using the term hiking is positively a joke!”

He added: “The three Americans have committed a violation. This violation has to be processed by our judiciary and it is taking its legal course.”

He also said that any form of pressure or attempt to influence the outcome of this process is unacceptable.

Last week a number of media sources announced that Joshua Fattal and Shane Bauer had been on a hunger strike for 17 days. However, their families said today that they both seemed to be in good health based on recent telephone conversations.