DUBAI, United Arab Emirates — An Iranian-American journalist who previously worked for a U.S. government-supported broadcaster has reportedly been held captive by Iranian authorities for several months, heightening tensions as Iran threatens to respond to an Israeli attack targeting the nation.

Authorities confirmed the detention of Reza Valizadeh, which the U.S. State Department acknowledged on Sunday, coinciding with Iran’s observance of the 45th anniversary of the takeover of the American Embassy and the hostage crisis. Just a day prior, Iran’s Supreme Leader Ayatollah Ali Khamenei issued stern warnings to both Israel and the U.S., promising “a crushing response,” as B-52 bombers were deployed to the Middle East to exert pressure on Tehran.

Valizadeh previously worked with Radio Farda, a media outlet under Radio Free Europe/Radio Liberty, which is funded by the U.S. Agency for Global Media. In February, he indicated on the social media platform X that certain family members had been detained in an attempt to compel him to return to Iran.

In August, Valizadeh seemed to post messages suggesting that he had indeed returned to Iran, even though Radio Farda is regarded as a hostile entity by the Iranian regime. One of his messages stated, “I arrived in Tehran on March 6, 2024. Before that, I had unfinished negotiations with the (Revolutionary Guard’s) intelligence department,” indicating that he had returned to his homeland after a 13-year absence without any safety guarantees.

He further named an individual whom he claimed worked for Iran’s Intelligence Ministry; however, the validity of this claim could not be independently verified.

Speculation around Valizadeh’s detention has been widespread for weeks. The Human Rights Activists News Agency, known for monitoring human rights issues in Iran, reported that Valizadeh was detained upon his arrival in the country earlier this year, followed by a temporary release. However, he was later rearrested and sent to Evin prison, where he is currently embroiled in a case within Iran’s Revolutionary Court, which is notorious for conducting secretive hearings based on undisclosed evidence. Notably, Valizadeh had previously faced arrest back in 2007, according to reports.

In response to inquiries about Valizadeh’s situation, the State Department confirmed it was “aware of reports” regarding the arrest of this dual U.S.-Iranian citizen. They stated, “We are working with our Swiss partners who serve as the protecting power for the United States in Iran to gather more information about this case,” and underscored that Iran routinely detains U.S. citizens and foreign nationals without just cause, labeling such actions as cruel and contrary to international norms.

Iran has yet to acknowledge Valizadeh’s detention, and the Iranian mission to the United Nations did not provide a comment on the matter. The Voice of America, another media outlet funded by the U.S. government, was the first to report that the State Department had confirmed Valizadeh’s arrest in Iran.

Since the 1979 U.S. Embassy crisis that resulted in the prolonged captivity of numerous hostages, Iran has repeatedly utilized individuals with Western affiliations as leverage in international negotiations. Most recently, in September 2023, five Americans who had been imprisoned in Iran for several years were released in exchange for five Iranians held in the U.S. custody and the unlocking of $6 billion in frozen assets held by South Korea.

Valizadeh is now the first American known to be detained in Iran since these events unfolded.