Secretary of State John Kerry on Friday urged Iran to free Amir Hekmati, a former American Marine, from four years of "unjust detention."
Saturday marks the fourth anniversary of Hekmati's imprisonment on what Kerry called "false espionage charges" while Hekmati was visiting relatives in the Islamic Republic.
"We repeat our call on the Iranian government to release Amir on humanitarian grounds," Kerry said in a statement quoted by the AFP news agency.
"This is a milestone no family wants to mark, and the Hekmati family has shown inspiring perseverance in the face of this injustice," he added.
"And as befits a former Marine, Amir has shown tremendous courage in the face of this unjust detention," said Kerry, who reiterated his government's call for Iran to release two other Americans.
These include pastor Saeed Abedini, who was arrested in 2012 and sentenced to eight years in jail for gathering a group of people to study the Bible, and Washington Post reporter Jason Rezaian, who faces trial in Iran on charges of espionage.
Kerry also urged Iran to "work cooperatively" to help locate Robert Levinson, a former FBI agent who disappeared while on Iran's Kish island in 2007.
Several lawmakers and Republican presidential candidates have argued that Washington and the international community should have negotiated the return of the Americans as a condition for finalizing the historic nuclear deal with Iran.
Hekmati, who was arrested in 2011, was put on trial and found guilty of spying for the CIA. He was subsequently sentenced to death, a penalty that was recently overturned and reduced to 10 years in prison.
Hekmati’s family and the U.S. government say the dual U.S.-Iranian citizen is not a spy and went to Iran to visit his grandmother.
(Arutz Sheva’s North American desk is keeping you updated until the start of Shabbat in New York. The time posted automatically on all Arutz Sheva articles, however, is Israeli time.)