BEIRUT (Reuters) - Iran demanded on Saturday that the United States release Iranians detained there, a day after U.S. president Donald Trump called on the Islamic Republic to release three U.S. citizens.

FILE PHOTO: A young boy stands behind an Iranian flag at Tehran's Mehrabad International Airport, Iran, May, 5, 2010. REUTERS/Morteza Nikoubazl/File Photo

“America should quickly release Iranian prisoners in the country,” foreign ministry spokesman Bahram Qassemi said, according to the Iranian Students’ News Agency (ISNA).

On Friday, Trump urged Tehran to return Robert Levinson, an American former law enforcement officer who disappeared in Iran more than a decade ago, and to release businessman Siamak Namazi and his father, Baquer, both jailed on espionage charges.

Trump warned that Iran would face “new and serious consequences” if the three men were not released.

The statement capped a week of U.S. rhetoric against Tehran, which announced last Sunday that another U.S. citizen, Xiyue Wang, a graduate student from Princeton University, had been sentenced to 10 years in jail on spying charges.

On Tuesday, Washington slapped new economic sanctions on Iran over its ballistic missile program and said Tehran’s “malign activities” in the Middle East undercut any “positive contributions” coming from the 2015 nuclear accord.

Last October, an Iranian court sentenced 46-year-old Siamak Namazi and his father Baquer Namazi, 80, to 10 years in prison on charges of spying and cooperating with the United States.

Iran’s Islamic Revolutionary Guard Corps detained Siamak in October 2015 while he was visiting family in Tehran, and Baquer, a former Iranian provincial governor and ex-UNICEF official, in February last year, family members said.

Levinson, a former agent for the Federal Bureau of Investigation and for the Drug Enforcement Administration, disappeared in Iran in 2007. The U.S. government has a $5 million reward for information leading to his safe return.

Robert Levinson left Iran years ago and the Islamic Republic has no information about his whereabouts, foreign ministry spokesman Qassemi said Saturday.

“The statements of the White House, as usual, are an example of interference in Iran’s internal affairs and the demands are unacceptable and rejected,” Qassemi said, according to ISNA.