It's time for the United States to hold Iran accountable.

An Iranian court upheld a 10 year prison sentence for Chinese-American student Xi Yue Wang on Sunday on charges of collaborating with foreign governments.

Wang, a student at Princeton University, was arrested last July while researching his PhD dissertation. The U.S. state department says he is one of a number of Americans and other foreigners being held on what it deems “fabricated national-security related changes.”

Iran’s detention of U.S. citizens has become a flashpoint in tensions between the nations, which have deteriorated since Trump took office in January.

Trump warned Iran in a July speech that it will face "new and serious consequences" unless all "unjustly detained" American prisoners are immediately released.

"For nearly forty years, Iran has used detentions and hostage taking as a tool of state policy, a practice that continues to this day with the recent sentencing of Xiyue Wang to ten years in prison," the White House said in July.

Iran's Foreign Minister Mohammad Javad Zarif has responded by accusing the U.S. of holding Iranians on "charges of sanction violations that are not applicable today... for bogus and purely political reasons.”

Things looked different back in 2016, when the two countries conducted a prisoner swap off the back of the nuclear deal struck between Iran and a U.S.-led coalition of nations. But the U.S. has since warned that American-Iranians remain especially vulnerable to arrest and detention in Iran.

Iran does not recognize dual nationality, meaning that American-Iranians do not receive consular assistance when arrested and are often tried behind closed doors in Iran’s Revolutionary Court, which handles cases of attempted government subversion.

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