US Special Envoy for Iran Robert Malley has called on the Islamic Republic to release US and UK citizens who are imprisoned in Iran.

Malley said in a tweet on Monday that the Iranian government has held environmentalist Morad Tahbaz for four years, stressing that he is a father and a cancer victim.

Iran has arrested many dual nationals and foreignners throughout the years, charging them with vague espionage and political offenses.

In a similar call for the fourth anniversary of Tahbaz’s “unfair detention in Iran”, UK Foreign Secretary Liz Truss said that “Iran must release him and all unfairly detained British nationals to allow them to return to their families. This appalling ordeal must be brought to an end.”

Malley also urged the release of Iranian American businessman Siamak Namazi, who is imprisoned in Iran since October 2015 on charges of collaboration with a foreign government, and his 84-year-old father, Bagher Namazi, a retired senior UNICEF official, also arrested and jailed in 2017 after he went to Iran to visit his son. Both are serving ten-year sentences.

Malley also called on the authorities to free Emad Sharghi, a 56-year-old Iranian American businessman who was arrested in December 2020 and sentenced to 10 years in prison on charges of espionage and collecting military intelligence.