More and more former Marines are joining a growing hunger strike, taking turns fasting as a sign of solidarity with one of their own imprisoned overseas.

For more than three years, Amir Hekmati, 31, of Flint, Michigan, who left the Corps as a sergeant, has languished behind bars in an Iranian prison. First accused of spying while visiting relatives, Hekmati later was convicted of aiding a hostile nation and given a 10-year sentence.

Maintaining his innocence, Hekmati appealed, but the case remains in limbo.

Told that his imprisonment is tied to nuclear negotiations between Washington, D.C., and Tehran, Hekmati revealed plans last week to protest with a hunger strike, according to a letter he purportedly wrote the head of Iran's judiciary. He wrote President Barack Obama as well.

"I have been told that, if I continue with this protest, I will be placed in solitary confinement," Hekmati said in the letter, which was republished by IranWire, a news website edited by expatriate Iranian journalists. "But I am deeply concerned with the lack of progress in my case and feel that I must take some action."

As word of his protest spread, fellow former Marines began following his lead, hoping to raise awareness of Hekmati's plight. Though he suspended his hunger strike Tuesday after Iranian authorities agreed to review his case, according to The Associated Press, former Marines in this country will continue fasting.

"We just rallied," said Nick Kaywork, former sergeant with the 2nd Radio Battalion. "We can't let this go quietly. We need to stand in solidarity with him."

Adopting Facebook, Twitter and other social media outlets to spread the word and organize — using the hashtags #hungerstrike and #FreeAmir — Kaywork and his fellow veterans take turns fasting for 24-hour stretches. More than 200 are participating.

Though multiple people might go hungry on any particular day, the idea is to have at least one former Marine "on-duty" and fasting at all times, Kaywork said.

"It's Marines standing in solidarity with a Marine who is in trouble, to show [Hekmati] that he is not alone and we're thinking about him," said Kaywork, who befriended the Iranian-American while the two underwent linguistics training together in the Corps. "He loves his family, loves his country … he served honorably and was discharged as a sergeant. It sounds so trite to say it, but he's a good guy. He really doesn't deserve the treatment he's been getting the last three years."

Along with showing solidarity, organizers hope the hunger strike raises awareness of Hekmati's plight. Brandon Walker, a former staff sergeant who left the Corps earlier this month, called it their main goal.

"I wanted to get involved and see if maybe we could come together as Marines and try to bring his case and his story back to life for not only America but the world in general," he said.

And they are concerned about his health. Hekmati describes his living conditions in his latest correspondence: forced in with hardened criminals, he fends off tics, lice and disease in a cold and dark prison ward.

As Hekmati struggles with illness, his father suffers from a brain tumor here. On a website dedicated to freeing Hekmati, supporters write that "his father fears he will never hold Amir in his arms again."

"[Hekmati] has made it clear … he can handle the stress of his hunger strike but what he can't handle is being away from his family and being away from his dying father," Walker said, who worries about his mental state as well as his physical health.

Not content at joining Hekmati's hunger strike, Walker, Kaywork and other supporters will demonstrate outside the White House on Dec. 29. Walker wants to see Washington do more on Hekmati's behalf.

In the meantime, he said he hopes Hekmati knows Marines everywhere are standing with him in spirit.

"If he's going through hardships then we're going to go through hardships with him, the same way we all went through boot camp," Walker said. "Marines don't go through things alone."