DETROIT — A US Marine veteran held in Iran for two years said in a letter to the US secretary of state that he has endured ‘‘miserable prison conditions’’ and believes Tehran is holding him hostage for use in a possible prisoner exchange.
Amir Hekmati’s letter, dated Sept. 1, was addressed to John Kerry and published Wednesday by Britain’s Guardian newspaper.
Hekmati, 30, wrote that he has been ‘‘held on false charges based solely on confessions obtained by force, threats, miserable prison conditions, and solitary confinement.
‘‘This is part of a propaganda and hostage-taking effort by Iranian intelligence to secure the release of Iranians abroad being held on security-related charges,’’ he wrote in the letter that the Guardian said was smuggled from the prison.
The US State Department said it had received the letter.
‘‘We have asked . . . Iranian authorities to permit a visit by officials of the Swiss Embassy in Tehran to determine the well-being of Mr. Hekmati and, of course, to release him,’’ spokeswoman Jen Psaki told reporters Wednesday.