Amid talks of a prisoner swap deal with the United States, the Iranian regime has detained another American citizen, further complicating efforts to lower tensions. 

Semafor news website in Washington DC cited three people briefed on the case as saying that the new arrest is now a crucial part of stepped-up negotiations between the two countries. 

The article, published on Friday, did not disclose the identity of the American, saying that it withheld the name to avoid jeopardizing negotiations over his/her release. Previously, the US has prioritized securing the release of three Iranian Americans, businessmen Siamak Namazi and Emad Sharqi, as well as environmentalist Morad Tahbaz, held by Iran on trumped-up charges of espionage. Two individuals with US permanent residency -- Jamshid Sharmahd and Shahab Dalili -- are also imprisoned in Iran. 

The negotiations -- which have taken place without public announcements in Oman as well as other countries -- are geared towards facilitating the exchange of Iranians convicted of crimes in Western countries for the release of US nationals held hostage in Iran, as well as the release of billions of dollars of Iran’s funds frozen in overseas banks.

While Iran has around $20 billion frozen in Iraqi, South Korean and Japanese banks due to US sanctions, what has often been mentioned as being discussed is $7 billion in two Seoul banks.

Despite claims by several Iranian officials who have for months publicly suggested that a deal was in the making, the Biden administration said in June that it continues contacts with Tehran, but no nuclear or prisoner release agreement is imminent. 

According to Semafor’s sources, the inclusion of the fourth American in the talks may prompt Tehran to raise its demands. 

The Biden administration has so far declined to reply to Semafor’s inquiry about the case of the fourth American citizen, but National Security Advisor Jake Sullivan implicitly confirmed it last week during an interview on Face the Nation. “We have tried very hard to secure the release of the four unjustly detained Americans in Iran, we have done so since the day that President Biden took office,” he said on Sunday. 

A person directly briefed on the case and close to one of three Iranian American families told Semafor on Thursday that “Multiple senior officials at the State Department in the last few weeks have privately emphasized that the US and Iran have already agreed the fourth American will be part of any deal and there are no delays being caused by [the person’s] inclusion.” 

In the past decade, Iran's Revolutionary Guard have arrested dozens of dual nationals and foreigners, mostly on unproven allegations of espionage and breach of security, in what human rights organizations have said is essentially hostage taking to extract concessions from Western governments. 

In November 1979, a group of leftist students backed by the new revolutionary government occupied the US embassy in Tehran and took 54 Americans hostage for 444 days. Later, the same strategy was used in Lebanon where multiple Westerners were taken hostage in the 1980s by militant groups linked to Tehran.

Tehran denies any policy of hostage taking and insists all foreigners are tried legally. However, it has frequently shown readiness for prisoner exchanges and receiving monetary payments and participated in swaps in the past.

In March 2022, Nazanin Zaghari-Ratcliffe, an Iranian-British citizen held in Iran for nearly six years, was freed along with British-Iranian businessman Anoosheh Ashoori after the UK paid a four-decade-old £400m ($522 million) debt to Iran. Iran's foreign minister Hossein Amir-Abdollahian claimed at the time that the payment by Britain had nothing to do with the release of the Zaghari-Ratcliffe and Ashoori.

The latest case was in June when two Iranian-Austrian citizens named Kamran Qaderi and Masoud Mosaheb and a Danish individual were released in the framework of a recent prisoner exchange agreement with Belgium mediated by Oman. A week earlier, Olivier Vandecasteele, a Belgian aid worker, returned to his country in exchange for the release of Assadollah Asadi, an Iranian agent disguised as a diplomat in Europe who was convicted of a terror plot in France in 2018.