The State Department confirmed yesterday (Sunday) to Agence France-Presse that it is gathering information on the case of an American-Iranian journalist allegedly being held at Iran.

“We are aware of information that this American-Iranian citizen is being held in Iran,” the US State Department responded to an AFP question, adding that it is working with Swiss authorities, who represent US interests in the country in the absence of diplomatic relations between the two countries, to “gather more information on the case.”

According to human rights advocacy organizations, Reza Valizadeh was arrested in September and is being held in Tehran’s Evin prison.

The American-Iranian journalist had previously worked for Radio Farda, which broadcasts in Persian and is funded by the U.S. government.

According to HRANA (Human Rights Activists News Agency), which records data on arrests in the Islamic Republic, Mr. Valizadeh had returned to Iran at the beginning of the year, was arrested a first time, released, then re-arrested in September and imprisoned in Evin.

The Committee to Protect Journalists (CPJ) said he had worked as a journalist for 16 years in the US. The press workers’ rights advocacy group called on Tehran to proceed with his “immediate release” and drop the charges against him.

Washington, which has had no diplomatic relations with Tehran since the 1979 Islamic Revolution, strongly urges U.S. citizens not to travel to Iran.

Relations between the two countries, openly hostile, are in a phase of further escalation, with Iran’s supreme leader Ali Khamenei vowing the day before yesterday, Saturday, that there would be a “fierce” retaliation to any attack by the US and Israel.

Thousands of Iranians gathered in central Tehran and other cities yesterday to mark the 45th anniversary of the 1979 US embassy hostage crisis.

A US ally, Israel has been waging war for more than a year against the Palestinian Hamas movement in the Gaza Strip and the Shiite Hezbollah movement in Lebanon. Both movements are backed by Tehran.