Washington Post reporter Jason Rezaian, who was jailed in Iran for 18 months, has filed a lawsuit against the Iranian government, saying his detention was aimed at "extorting" concessions from the United States in nuclear talks.

The lawsuit filed on October 3 in U.S. federal court by Rezaian and his family seeks unspecified damages from Iran for, among other things, "cruelty, torture, and abuse" during his detention.

"For nearly 18 months, Iran held and terrorized Jason for the purpose of gaining negotiating leverage and ultimately exchanging him with the United States for something of value to Iran," the suit states.

Rezaian was among four Iranian-American dual nationals freed in Tehran in January in a prisoner-swap deal that took place hours before the implementation of a landmark nuclear deal that limits Iran's nuclear program in exchange for sanctions relief.

Iranian officials had accused Rezaian of espionage and other offenses. The lawsuit says the charges were "blatant lies" and part of an effort to increase his value as part of an exchange with the United States.

"In reality, Jason committed no crime and was never legitimately tried, convicted, or sentenced -- even according to Iranian standards," the lawsuit said.

Based on reporting by The Washington Post and AFP