A United Nations rights panel has issued a strongly worded opinion calling on Iran to immediately release an American scholar imprisoned two years ago while doing historical research that the Iranian authorities had approved.
The opinion, by the United Nations Working Group on Arbitrary Detention, said the scholar, Xiyue Wang, a graduate student at Princeton University, had been wrongly accused of espionage, secretly tried and imprisoned.
"The Working Group requests the Government of the Islamic Republic of Iran to take the steps necessary to remedy the situation of Mr. Wang without delay and bring it into conformity with the relevant international norms," stated the opinion, dated Aug. 23.
The United Nations has not publicly released the opinion but Princeton University posted a summary of the findings on its website, along with a plea from Princeton officials and Mr. Wang's wife for his release.
There was no immediate response by Iranian government officials to the United Nations opinion.
While not binding, the opinion cast an unflattering light on Iran's opaque judiciary, which has never provided evidence to explain precisely why Mr. Wang was arrested.
Mr. Wang is one of at least four American citizens known to be detained by the Iranian authorities.
He traveled to Iran in 2016 to conduct research for his doctoral dissertation and — with government permission — was reviewing publicly viewable documents from the late 19th and 20th centuries in Iran's National Archives. He was seized in August 2016, confined to Tehran's Evin Prison, convicted at a closed trial and sentenced to 10 years.
Princeton University officials, who had kept knowledge of Mr. Wang's plight secret for nearly a year in hopes that he would be quietly freed, spoke out in July 2017 after Iranian news media reported Mr. Wang had been convicted of spying for the United States.
American officials, Princeton and Mr. Wang's family and supporters have all denied Iran's accusations, calling them baseless and politically motivated.
The United Nations panel's opinion said Iran had showed neither how Mr. Wang had spied, nor how his legally permitted access to "historical archives relating to a period of governance over 100 years ago could amount to an attempt to overthrow the Iranian government."
Princeton also published a statement on Monday by Mr. Wang's wife, Hua Qu, who has helped lead the public campaign for his release while raising their young son alone.
"It is absurd to imagine my husband engaging in espionage by researching archival documents more than 100 years old for a history dissertation," she said. "He is not a spy but a linguist, a historian who loves Persian culture, a devoted husband and loving father."
Reached by telephone, she called the United Nations panel's opinion an important pressure point on Iran, but acknowledged that "these are just words — they cannot by themselves help my husband come back."
The incarceration of Mr. Wang has helped chill scholarly exchanges between Iran and the United States, which had managed to continue despite the increasingly tense overall relationship.
Last week the Middle East Studies Association of North America, in a letter to Iran's supreme leader, Ayatollah Ali Khamenei, emphasized that Mr. Wang "had received the necessary visa as well as a research permit to conduct archival research" before he went to the country.
"He should be reunited with his young family and allowed to continue his important academic work," stated the letter from the association's president, Judith E. Tucker of Georgetown University.