President Donald Trump warned Friday that Iran risked facing “new and serious consequences” if it did not release all wrongfully detained Americans there and allow them to leave the Muslim country.

Specifically, Trump called for American law enforcement officer Robert Levinson to be freed after a decade in Iran, and for businessman Siamak Namazi and his father, Baquer, to be released as well.

A White House statement issued Friday said Trump and his administration were “redoubling efforts” to free all Americans unjustly detained overseas.

“Iran is responsible for the care and wellbeing of every United States citizen in its custody,” the statement said.

The statement was just the latest example of the U.S. sharpening its rhetoric against the Iranian government while still adhering to a 2015 nuclear deal negotiated with Iran by the U.S. and other world powers, Reuters reported.

Earlier in the week, Washington imposed new economic sanctions on Iran over its ballistic missile program, saying Tehran’s recent actions in the Middle East undermined any “positive contributions” that may have resulted from the nuclear accord.

Levinson, a former agent for the FBI and Drug Enforcement Administration, disappeared in Iran in 2007. The U.S. government has offered $5 million for information leading to his return.

Siamak Namazi, 46, and Baquer Namazi, 80, were each sentenced to 10 years in prison after being convicted in an Iranian court of spying and cooperating with the United States. Siamak was arrested in Tehran in October 2015, while his father -- a former Iranian provincial governor and former Unicef official – was detained in February 2016, family members told Reuters.

Xiyue Wang, a Chinese-born U.S. citizen graduate student from Princeton University, received a 10-year sentence in Iran for spying, Reuters reported, citing Iran's judiciary spokesman.