(Bloomberg) -- Five Americans freed in a prisoner-swap deal with Iran landed safely in Qatar, the latest step in a diplomatic effort that Washington hopes could ease regional tensions and open space for progress on the Islamic Republic’s nuclear program.

The detainees landed just before sunset in heat of 104 degrees Fahrenheit (40 degrees Celsius) in Doha on Monday afternoon. They were greeted by Qatari and American officials, and one waved to journalists in the tarmac before the group was escorted away.

“Today, five innocent Americans who were imprisoned in Iran are finally coming home,” President Joe Biden said in a statement. He thanked Qatar and Oman for helping negotiate the agreement “over many months of difficult and principled American diplomacy.”

“And, we will continue to impose costs on Iran for their provocative actions in the region,” he said.

As part of the swap, the Biden administration is releasing five Iranians held in US custody. But the most controversial element was the US move to allow Iran to access $6 billion in oil revenue that had been frozen in South Korean banks due to sanctions.

The US says that money can be used solely for food, medicine and other humanitarian purposes, but Iran has said it can spend the funds as it wishes. In any case, critics in Washington contend it will free up funds Iran can spend on what they call its malign activity in the region. 

The moves follow months of mostly secret diplomacy between Tehran and Washington, with talks conducted via interlocutors such as Oman and Qatar.

Although US officials have said there’s no bigger deal in the works, they’ve also said that freeing the prisoners removes at least one obstacle to broader diplomacy aimed at restoring limits on Iran’s nuclear program. 

Read more: Tracking the Twists and Turns of the US-Iran Conflict

The US acknowledges it won’t be viable to restore the 2015 nuclear deal, which set bounds on Tehran’s uranium enrichment but was abandoned by President Donald Trump in 2018. 

Instead, they’ve sought to make informal progress to impose meaningful limits while also avoiding blowback from Republicans and some Democrats who argue that the administration shouldn’t do deals with a government that’s listed as a state sponsor of terrorism and has perpetrated widespread rights abuses against its own people.

“When it comes to perhaps the No. 1 issue of concern, which is Iran’s nuclear program, we continue to believe that diplomacy is the best way to get a sustainable, effective result,” Secretary of State Antony Blinken told reporters in New York, where he, Biden and other world leaders are gathering this week for the annual meeting of the United Nations General Assembly meeting. 

“We’ll continue to see if there are opportunities for that,” Blinken said.

 

Iran denies it wants a nuclear weapon but has rapidly increased its enrichment in the five years since Trump quit the nuclear deal. Discussions on Iran’s nuclear work are “possible” via intermediaries on the sidelines of the this week’s UN sessions, the Iranian foreign ministry said on Monday.

The prisoner agreement was a victory for Iran’s President Ebrahim Raisi, who was also set to be in New York for the UN meetings. 

In an effort to show that it’s not letting up on pressure against Iran, the US also announced sanctions Monday against former President Mahmoud Ahmadinejad and Iran’s Ministry of Intelligence. 

Prisoners Identified

Among those who arrived on the flight to Qatar was Siamak Namazi, who had been held in Evin Prison in Tehran since 2015. Also onboard were Morad Tahbaz and Emad Shargi, as well as two Americans who wanted to remain anonymous.

“Thank you President Biden for ultimately putting the lives of American citizens above politics,.” Namazi said in a statement. “Thank you for ending this nightmare. Thank you for bringing us home.”

US officials are also bringing home two of the detainees’ relatives who had been prevented from leaving Iran, according to senior administration officials.

Read more: Iran Braces for Protests on Anniversary of Mahsa Amini’s Death

In August, Iran moved the Americans out of prison to house arrest. 

The next stage of the deal will see the release from US custody of five Iranian nationals who have either been convicted or are awaiting trial. Some of them may choose to stay in the US, according to US officials familiar with the negotiations.

The swap happened almost exactly a year after the death of Mahsa Amini, who had been arrested for allegedly flouting Islamic dress codes. That set off months of nationwide protests.

It’s all part of the Biden administration’s push to ease tensions more broadly in the Middle East. The US and allies including Israel worry that Iran intends to build a nuclear weapon, which could trigger an arms race in the region. 

Iran’s oil exports have soared amid the latest diplomatic push, with most shipments headed to China. Some US officials have privately acknowledged they’ve gradually relaxed enforcement of energy sanctions on Tehran.

--With assistance from Jonathan Tirone and Patrick Sykes.

(Updates with Blinken comment in 11th paragraph.)

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