Washington Post reporter Jason Rezaian is suing Iran on charges of torture and abuse after he was imprisoned in the Islamic Republic for a year-and-a-half. The paper's former Tehran bureau chief filed the lawsuit Monday in the US District Court in the District of Columbia seeking damages from Iran. He has accused his captors of holding "him hostage for the purpose of extorting concessions" during nuclear negotiations with the US.Coinciding with the implementation of the nuclear deal between Iran and world powers, Rezaian was released in January along with three other American prisoners as part of a prisoner swap. The suit accused Iranian authorities "held him hostage for the unlawful purpose of extorting concessions," using his 18-month incarceration to increase his value as a bargaining chip in a possible exchange with the US.The lawsuit filed by Rezaian and his family names Iran's infamous Revolutionary Guard Corps as a co-defendant, accusing the paramilitary body of causing the Washington Post correspondent "severe personal injuries and other irreparable harm" by means of abuses such as "unlawful acts of terrorism, torture, hostage taking." Rezaian's complaint charges that Iran accused him of espionage among other unspecified offenses which he labeled as "blatant lies" and mechanisms used as part of "a futile effort to justify its crimes." "In reality, Jason committed no crime and was never legitimately tried, convicted, or sentenced -- even according to Iranian standards," AFP quoted the lawsuit as saying. Seeking damage under the Foreign Sovereign Immunities Act, Rezaian's lawsuit also states that the Iranian captor's "threatened to main and kill his wife Yeganeh [Salehi]," also a journalist, who was imprisoned for 72 days. According to US media, the lawsuit details particulars of Rezaian's detainment that had not before been publicly released. In 2014, Iranian authorities arrested the California-born dual US-Iranian citizen and later imprisoned him on accusations of espionage, charges the Post had dismissed as "absurd."Reuters contributed to this report.