An online gripe about work has landed a US citizen in a Middle Eastern jail.

Ryan Pate, a helicopter mechanic from Belleair Bluffs, Florida, took to Facebook after a dispute over sick leave with the company he was working for in the United Arab Emirates.

He was home in Florida at the time, but when he returned to Abu Dhabi last month, he was told to report to the police station, where he was arrested for breaking an Emirates law on slandering his employer.

He spent about 10 days in jail, he said, and is now free on bail awaiting a March 17 trial. His supporters say he faces up to five years in prison and a steep fine if convicted.

"I just couldn't register it in my head because as an American growing up in the United States, the First Amendment right is just ingrained in my brain," he said in a phone interview.

"I never even entertained the fact that I would wind up in prison out here for something I put on Facebook in the United States."

Pate, 30, said the incident stemmed from a trip to Florida in December.

During his return, he spent the holidays with family and proposed to his girlfriend, Jillian Cardoza, but also was trying to get treatment for a back injury.

There was disagreement with his bosses about extending his leave to see a doctor, he said, and after a particularly unsatisfactory phone call with them, he took to Facebook.

He claims he cannot remember precisely what he wrote, but knows he called his bosses "backstabbers" and warned other contractors not to work for them.

He gave the rant little further thought until he was back in the Persian Gulf, where he planned to handle paperwork to end his employment as well as empty his apartment and sell his car.

Soon after, he says he received a call from police telling him to come to the station, where officers showed him screen shots of his comments.

Pate's congressman, David Jolly, intervened on his constituent's behalf, lobbying the US state department and Emirates officials for help. In a letter to the Emirati attorney general, Mr Jolly emphasised respect for the sovereignty of the country, but argued because the posts occurred while Pate was on American soil, those laws should not apply.

"It is deeply troubling that Mr Pate now faces judicial proceedings over an action that was done legally in his home country," the Republican said.

The Emirati Embassy in Washington said it did not have much information about the case and could not comment.

A state department spokeswoman, Marie Harf, said a consular officer had visited Pate in prison and that the embassy in Abu Dhabi would continue providing assistance.

Pate said he is trying not to think too much about the sentence he could face, but did say he is remorseful for letting his emotions get the best of him.

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