DUBAI, United Arab Emirates -- An Iranian-American businessman who advocated better ties between Iran and the U.S. reportedly has been arrested and imprisoned in Tehran, becoming the fourth U.S. citizen known to be held there at a time when hard-liners are pushing back against the country's nuclear deal with world powers.
The reasons why Siamak Namazi would be detained were not immediately known.
Namazi, the son of a politician from the era of Shah Mohammad Reza Pahlavi, had been specifically criticized in commentary this year as Iranian conservatives warned against easing hostilities with the U.S.
Reports of Namazi's imprisonment follow the convictions of other Iranian-Americans, notably Washington Post journalist Jason Rezaian. Meanwhile, an Internet freedom group said a Washington-based Lebanese citizen recently disappeared while on a trip to Tehran.
Namazi was arrested earlier this month while visiting Tehran, according to The Wall Street Journal, The New York Times and The Washington Post, all of which relied on anonymous sources. Attempts to reach relatives of Namazi, who has a home in Washington, weren't immediately successful.
Iranian officials could not be reached for comment Friday, part of the Iranian weekend, and state media did not mention Namazi.
The U.S. State Department declined to confirm Namazi's arrest.
"We're aware of recent reports of the possible arrest in Iran of a U.S. citizen. We're looking into these reports and don't have anything further to provide at this time," Michael Tran, a State Department spokesman, said late Thursday.
Namazi is a son of Bagher Namazi, a former UNICEF representative who once served as governor of Iran's oil-rich Khuzestan province under the U.S.-backed shah. The family fled after the 1979 Islamic revolution but kept business ties in Iran, and the younger Namazi traveled back several times.
His last known employer was Crescent Petroleum, a firm based in Sharjah in the United Arab Emirates that has been locked for years in a legal dispute with Iran over natural gas production. A representative of the company said Namazi traveled to Tehran in mid-July on a private visit and "at the time of his reported detention was no longer an employee of the company."
The representative declined to be identified, citing the political sensitivities surrounding the matter.
Namazi identified himself as the managing director of Atieh Bahar, a consulting company in Iran, in a 2006 interview. An Atieh Bahar official, who refused to be identified, said Namazi had not worked with the firm "for eight or 10 years."
In articles he wrote for Iranian.com, Namazi says he graduated from Tufts University in 1993 and returned to Iran for a time.
"This land of my dreams was all I thought about. My passion for return was so great, it hurt," he wrote in 1997. "In Iran, you are either experiencing heaven or hell. There are very few in-betweens."
In recent years, Namazi wrote several pieces calling for improved ties between Iran and the U.S., and urging Iranian-Americans to act as a bridge between the rival governments. In 2013, Namazi wrote about shortages of medical supplies caused by international sanctions on Iran in an opinion piece published by the International Herald Tribune. He urged the West to "relax and rationalize" the sanctions to allow medical goods into Iran, or "more Iranian men, women and children will suffer needlessly."
Still, Namazi raised suspicions among many in Iran. In a May article, an Iranian website called Fardanews accused him of being part of efforts to allow the West to infiltrate Iran.
"Siamak has always played the role of bridge between the U.S. government with some notorious local figures in the country," the website said. "His allies and family have been ground-preparing for soft infiltration of the U.S. in Iran."
Iran announced earlier in October that Rezaian, The Washington Post's bureau chief in Tehran, was convicted by its Revolutionary Court on charges including espionage, though there have been no details on the verdict or sentence. He was detained in July 2014 and has now been detained longer than the 52 U.S. diplomats and citizens who were held hostage in Iran for 444 days after the Islamic revolution by followers of Ayatollah Ruhollah Khomeini.
Other Americans held in Iran include former U.S. Marine Amir Hekmati, who holds dual Iranian and U.S. citizenship and was arrested in August 2011. Saeed Abedini, a pastor from Boise, Idaho, was convicted in 2013 of threatening Iran's national security by participating in home churches.
The U.S. also says it has asked for the Iranian government's assistance in finding former FBI agent Robert Levinson, who vanished in 2007 while working for the CIA on an unapproved intelligence mission.
Information for this article was contributed by Nasser Karimi of The Associated Press.
A Section on 10/31/2015