ISTANBUL — A Chinese-American student accused of espionage by Iran was sentenced by an Iranian court to 10 years in prison, and President Hassan Rouhani’s brother was detained over allegations of financial misconduct, judicial authorities said Sunday.
Hossein Fereidoun was detained for unspecified financial crimes, a judicial spokesman said. Fereidoun is a close adviser of the president and was involved in the negotiations that led to the nuclear deal with world powers.
The nuclear deal is unpopular with hard-line conservatives in Iran, who have long accused Fereidoun of corruption, including money laundering and misappropriation of government funds.
Sunday’s developments came less than two months after the relatively moderate Rouhani beat a hard-line opponent to win reelection, running on a promise of greater engagement with the West. Iran’s judiciary is heavily influenced by hard-liners.
The imprisonment of the American scholar is likely to raise tensions with the Trump administration before a deadline for waiving some sanctions against Iran. Tehran’s nuclear deal with world powers in 2015 brought the country relief from international sanctions in exchange for limits on its atomic energy program.
The Mizan news agency identified the convicted American as Xiyue Wang, a 37-year-old graduate student in history and researcher at Princeton University. The report said he was born in Beijing and is a dual Chinese-American citizen.
Judicial spokesman Gholamhossein Mohseni Ejehi said Wang “was involved in infiltration,’’ the Associated Press reported.
Mizan, which is affiliated with Iran’s hard-line judiciary, reported that Wang had been sentenced as part of an ‘‘infiltration project’’ that included the gathering of ‘‘confidential articles’’ to send back to the State Department and Western academic institutions.
Wang, who was arrested on Aug. 8, 2016, is also accused of passing confidential information about Iran to Princeton’s Sharmin and Bijan Mossavar-Rahmani Center for Iran and Persian Gulf Studies, the Harvard Kennedy School, and the British Institute of Persian Studies, according to Mizan.
The government alleged that he recorded some 4,500 pages of digital documents.
The State Department was not immediately able to provide details on the case. It said its citizens’ safety is a top priority.
Facebook and LinkedIn pages indicate Wang studied at Harvard University from 2006 to 2008, and later worked as a Pashto language interpreter for the International Committee for the Red Cross in Afghanistan.
The website of Wang’s adviser at Princeton, Stephen Kotkin, lists Wang’s PhD thesis as ‘‘Islamic Inner Asia.’’
The Mizan report, which included a photo from the Princeton University website, included a quote from Wang in which he had praised the British Institute of Persian Studies for facilitating access to Iran’s National Archives and other libraries.
The quote was used as evidence of his spying activities, the report said. Princeton University did not respond to a request for comment.
‘‘I have been having trouble accessing Tehran’s archives and libraries,’’ Wang said in the 2015-2016 annual report of the British Institute of Persian Studies, a nonprofit organization based in London.
‘‘Mrs. Reyhanpour offered to help,’’ he said of one of the institute’s employees. ‘‘And within a few days, she put me in contact with senior scholars at the National Archive. . . . Without Mrs. Reyhanpour’s help it would be hard to imagine how long it would have taken for me to become acquainted with academic institutions in Iran.’’
Wang’s reported conviction comes at a particularly tense time for US-Iranian relations, which have rapidly deteriorated since Trump took office.
Under the previous administration, the United States and other world powers negotiated a deal with Iran to curb its nuclear program in exchange for sanctions relief. It was hailed as a victory for diplomacy and an end to Iran’s global isolation.
But since then, the Trump administration has stepped up its anti-Iran rhetoric and placed US participation in the nuclear deal under review.
Monday is the deadline for the White House to decide whether to issue a waiver on nuclear-related sanctions against Iran, a provision that is required periodically under the terms of the 2015 nuclear deal.
The administration is expected to approve the waiver, despite an internal debate on how to respond to Iran’s human rights abuses and support for militant groups like Hezbollah.
‘‘The Iranian regime continues to detain US citizens and other foreigners on fabricated national-security related changes,’’ a State Department official said. ‘‘We call for the immediate release of all US citizens unjustly detained in Iran so they can return to their families.’’
It was unclear how long Wang has been in Iranian custody. Wang is one of several Americans held by Iran.
Karan Vafadari, an Iranian-American art gallery manager, was detained along with his Iranian wife last year. They have yet to be convicted of a crime.
Siamak Namazi, an Iranian-American businessman, and his 81-year-old father, Baquer Namazi, are each serving 10-year sentences for ‘‘cooperating with the hostile American government.’’
Another Iranian-American, Robin Shahini, was released on bail last year after staging a weeks-long hunger strike while serving an 18-year prison sentence for ‘‘collaboration with a hostile government.’’