Ex-Marine Amir Hekmati Freed From Iran 'Proud to Be an American' Former Marine had been imprisoned for four years, accused of espionage.

 -- Amir Hekmati, a former Marine freed from an Iranian jail in the recent prison swap, said in his first public appearance as a free man that he tried to uphold the reputation of the Marine Corps while in captivity and told his brothers-in-arms, “Semper Fi” – the Marine Corps motto meaning Always Faithful.

"I didn't want to let any of my fellow Marines down, and the reputation of the Marine Corps. So I tried my best to keep my head up and withstand all the pressures that were on me, some of which were very inhumane and unjust," he said. "Hearing about some of my fellow Marines supporting me really gave me the strength to put up with over four years of some very difficult times that me and my family went through... Semper Fi to all the Marines out there."

Speaking from Germany, a happy, relaxed Hekmati described the tense day he was freed, as a last minute bureaucratic mistake delayed their plane. He said first they were delayed a couple hours, which eventually dragged on to 10.

"It was very nerve-wracking... Up until the last second we were all concerned" that the Iranian side might've tried to change the deal, Hekmati told reporters.

A sigh of relief when they finally lifted off turned into a celebration when the plane cleared Iranian airspace to cheers and the popping of champagne.

Asked how it feels to be free, he said, "It feels great. I feel very lucky. Like I said, I feel alive for the first time. It's like being born again, and I just really feel proud to be an American."

Hekmati said he was incredibly grateful to everyone who worked to gain his freedom, and he was in awe and “humbled” by the outpouring of support.

The former Marine, a dual American-Iranian citizen born in Arizona, was arrested in late 2011 while on a trip to see his grandmothers. The Iranian government claimed he was a spy and used a videotaped “confession” to support their case – though Hekmati’s family and U.S. officials denied he was a spy and said the confession was coerced. Hekmati’s father, now gravely ill, told ABC News after his arrest that the Iranian claims were “a bunch of lies.”

Hekmati was convicted in a secretive trial and sentenced to death in 2012, but the sentence was later overturned.

Hekmati was released over the weekend with four other Americans in exchange for the U.S. releasing seven Iranians either convicted or awaiting trial in the U.S. The U.S. also removed Interpol red notices and dismissed charges against 14 other Iranians abroad who a U.S. official said were unlikely to be extradited to the U.S.