An Iranian court sentenced a Chinese-American man to 10 years in prison on espionage charges, Iranian news agencies reported Sunday.

The news services, citing judiciary authorities, also said the brother of Iranian President Hassan Rouhani had been detained amid allegations of financial improprieties.

Iran's identified the Chinese-American as Xiyue Wang, 37, who had studied history at Princeton in recent years and entered Iran as a researcher. The website said Wang was arrested about a year ago and was an expert in Eurasia policies, Islam and nationalism, Russia, the Middle East and Iranian studies.

Iranian authorities accused Wang of passing information to the U.S. State Department, Princeton's Center for Iran and Persian Gulf Studies, and Harvard's Kennedy School of Government.

"This person, who was gathering intelligence and was directly guided by the U.S., was sentenced to 10 years in prison, but the sentence can be appealed," Iran's Judiciary Spokesman Gholamhossein Mohseni-Ejei said on state TV.

Princeton confirmed to USA TODAY that the American sentenced to 10 years by Iranian authorities is Xiyue Wang.

The State Department did not immediately respond to a request for comment.

The Iran nuclear deal, which turned 2 years old this month, has loosened restrictions on business dealings between the two countries. However, the U.S. does not maintain formal diplomatic relations with Tehran and routinely warns U.S. travelers that they risk being barred from leaving. 

Others detained include Iranian-American art gallery manager Karan Vafadari and his wife, who have been held since last year, and Iranian-American businessman Siamak Namazi and his father, Baquer Namazi, who are serving 10-year sentences for espionage.

“The Iranian regime continues to detain U.S. citizens and other foreigners on fabricated national-security related changes,” the State Department said in a statement to the Associated Press. “We call for the immediate release of all U.S. citizens unjustly detained in Iran so they can return to their families.”

Mohseni-Ejei also announced that Hossein Fereydoun, the brother of Rouhani, was sent to prison on Sunday over financial charges. Mohseni-Ejei said Fereydoun had been subject to various probes and some people around him also are being investigated for over undisclosed financial matters.

Fereydoun will be released if and when he posts bail, Mohseni-Ejei said.