Electrocuted and beaten: Ex-US Marine sues Iran over alleged torture

A former US Marine who was accused by Iran of spying and held for four and a half years is suing Tehran over the "prolonged and continuous physical abuse" he endured while detained.

According to a lawsuit filed in Washington on Monday, Amir Hekmati, a US-Iranian dual national from Michigan, was subjected to a slew of physical and psychological abuse while jailed in the notorious Evin Prison.

Hekmati was freed in a prisoner swap in January in which he and three other Iranian-American dual nationals, plus another American, were traded after Washington granted clemency to seven Iranians and withdrew arrest warrants for 14 others.

During his lengthy ordeal, Hekmati was "whipped at the bottom of his feet, struck by an electrical Taser to his kidney area, forced to stay in stress positions for hours at a time, and hit with batons," the lawsuit states.

The former Marine had been visiting relatives in Tehran in August 2011 when he was nabbed by Iranian officials.

He ultimately was forced to confess to being a CIA spy and sentenced to death, though the sentence was later reduced to 10 years in prison.

Aside from physical abuse, prison guards threw water on Hekmati's cell floor to prevent him sleeping, kept the light on and forced him to take lithium and other "addictive pills," only to stop these to trigger withdrawals, the lawsuit states.

"Iran's treatment of Amir Hekmati was utterly contemptible," his attorney, Scott Gilbert, said in a statement.

"Amir was arrested on phony charges, thrown into brutal solitary confinement in one of the world's most inhumane prisons, and then subjected to prolonged physical and psychological abuse."

Hekmati, who is unemployed and "suffering the financial effects of being robbed of four and a half years of income," is seeking unspecified compensatory and punitive damages.

Hekmati served in the US Marines from 2001 to 2005 as an infantry rifleman and translator.

His legal team argues that Iran's behaviour was outside the scope of immunity provided by the Foreign Sovereign Immunities Act (FSIA,) so Iran can be sued in the United States.