"Iran is responsible for the care and well-being of every United States citizen in its custody, the White House said in a statement on Friday.
President Trump urges Iran to return Robert Levinson home, who has been held for over 10 years, and demands Iran release Siamak and Baqer Namazi, who were taken during the Obama administration, along with all other American citizens unjustly detained by Iran," it added.
Levinson is a former FBI agent who reportedly went missing during a visit to Irans southern Kish Island in 2007. Tehran has categorically denied any involvement in his disappearance and promised to help determine his fate.
Last year, the White House said it had reason to believe that Levinson was no longer in Iran, and apparently had thought so for years.
The US government had insisted for years that Levinson was working as a private investigator. However, in December 2013, his family admitted that he was working for a rogue CIA operation as a freelance "spy." The US has a $5 million reward for information leading to his return.
The White House statement also mentioned Chinese-born US citizen Xiyue Wang, who was sentenced Monday to 10 years in prison for espionage under the cover of research. Irans Judiciary said Wang was caught trying to smuggle 4,500 pages of confidential documents out of the country.
[caption id="" align="aligncenter" width="555"]
Iranian Judiciary spokesman Gholam-Hossein Mohseni-Ejei gives a press conference on July 16, 2017. Mohseni-Ejei announces the arrest and sentencing of a US spy in the presser.[/caption]Siamak and Baqer Namazi also received ten-year prison terms for espionage last year. Iran's Foreign Minister Mohammad-Javad Zarif said on Wednesday that Baqer Namazi was not imprisoned, but was banned from leaving the country.
The Friday statement capped a week of rhetoric against Iran. On Tuesday, the Trump administration imposed new economic sanctions against the Islamic Republic over the countrys missile program.
The move came only one day after the administration certified to Congress that Iran was in compliance with the 2015 nuclear agreement, which lifted nuclear-related sanctions imposed against Tehran.
The US claims Irans missile program is in breach of United Nations Security Council Resolution 2231, which endorsed Tehrans nuclear deal with the P5+1 states in 2015.
However, Tehran insists its missile tests do not breach any UN resolutions because they are solely for defense purposes and not designed to carry nuclear warheads.
