Iran has imposed a 10-year prison sentence on US citizen Xijue Wang.

Judiciary spokesman Gholam Hossein Mohseni Ejei said on Sunday that “a US infiltration agent.directly instructed by America” had been convicted of espionage.

Mohseni Ejei did not name the individual but Mizan News Agency identified him as Wang, a fourth-year doctoral student of the Sharmin and Bijan Mossavar-Rahmani Center for Iran and Persian Gulf Studies at Princeton University. He has been completing a dissertation in Eurasian history of the late 19th and early 20th centuries.

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Wang was arrested on August 8, 2016 as he was leaving Iran. Mizan claimed that he had digitally archived 4,500 pages of documents from research institutions and archives.

The outlet said Wang had given information to the Mossavar-Rahmani Center, to Harvard University’s Kennedy School, to the British Institute of Persian Studies, and to the State Department. It cited an excerpt of a March 2016 published report from the British institute that Wang had been in contact with “senior scholars” at Iranian government archives in Tehran and Mashhad.

A spokesman for Princeton University said it had known about the arrest for months and “had been trying to work quietly to have Mr. Wang freed”.

Ejei said the sentence could be appealed.

Iranian authorities have detained and sentenced a series of dual nationals. Although five American citizens were released in January 2016, as Iran’s nuclear deal with the 5+1 Powers was implemented, Tehran has put others in prison. They include Anglo-Iranian charity worker Nazanin Radcliffe, given 5 years; Iranian-American oil executive Siamak Namazi and his 81-year-old father Baqer, a Canadian-Iranian who is a former UNESCO official, each serving 10 years; Lebanese-Iranian national and US resident Nazar Zaka, given 10 years; and Iranian-American Karan Vafadari and his wife Afarin Neyssari, art gallery owners in Tehran who are awaiting sentences.

The US State Department said in a statement:

The Iranian regime continues to detain US citizens and other foreigners on fabricated national-security related changes. We call for the immediate release of all US citizens unjustly detained in Iran so they can return to their families.