Iranian news agencies on Monday reported that an Iranian citizen detained in Germany for violation of sanctions and facing extradition to the United States was freed and returned to Iran with Foreign Minister Mohammad Javad Zarif on Sunday evening.

Ahmad Khalili was arrested in Germany in 2018 for trying to circumvent U.S. sanctions the reports say without further information. It is also not clear if Iran has also freed any foreign prisoner in exchange or made any promises.

Iranian Foreign Ministry Spokesman Abbas Mousavi on Monday said that Khalili was released after intense diplomatic negotiations and with "cooperation of the judiciary and IRGC Intelligence Organization".

Khalili had been detained in Germany by the request of U.S. prosecutors on the "on the pretext of violating illegal and unfair sanctions of the United States was freed last night, ” Mousavi said.

According to Mousavi, Khalili returned to Iran on Sunday evening with Foreign Minister Zarif who was in Germany to attend the 56th Munich Security Conference.

After Iran released Chinese-American graduate student Xiyue Wang who had been held for three years on espionage charges in December 2019, the Iranian Foreign Minister said: "After getting our hostage back this week, fully ready for comprehensive prisoner exchange".

Wang was freed in exchange for Iranian scientist Massoud Soleimani who had faced a U.S. federal trial in Georgia over charges he violated sanctions by trying to have biological material brought to Iran.

Iran and the United States negotiated the prisoner swap indirectly through Switzerland.

Other American detainees in Iran include U.S. Navy veteran Michael White, who is serving a 10-year sentence, environmentalist Morad Tahbaz, an Iranian with U.S. and British citizenship and 83-year-old Baquer Namazi and his son, Siamak Namazi, dual Iranian-American nationals who were convicted of collaborating with a hostile power.