Iran and Sweden announced on Saturday a prisoner exchange that saw a former Iranian official jailed in Sweden freed as Stockholm said Tehran had released a European Union diplomat and a second Swede.
"Hamid Noury, who has been in illegal detention in Sweden since 2019, is free and will return to the country in a few hours," Kazem Gharibabadi, head of Iran's High Council for Human Rights, said in a post on social media platform X.
Shortly afterwards, Sweden's prime minister said Johan Floderus, an EU diplomat, and another Swedish national who were held in Iran had been released and were on a flight home.
Floderus, 33, had been held in Iran since 2022 April accused of espionage. He risked being sentenced to death.
The other Swede, Saeed Azizi, had been arrested in 2023 November.
They were on their way home "and will finally be reunited with their relatives", Swedish Prime Minister Ulf Kristersson said.
Gharibabadi said the release of Noury was thanks to efforts led by late Iranian foreign minister Hossein Amir-Abdollahian, who died in a helicopter crash alongside president Ebrahim Raisi in May.
The official Oman News Agency (ONA) later said Tehran and Stockholm had agreed, following mediation by Oman, to the "mutual release" of nationals detained in both countries.
"Those released were transferred from Tehran and Stockholm to Muscat today, 15 June 2024, for their repatriation," ONA said.
Noury's son, Majid, hailed in a post on X Iranian officials' "powerful and zealous" efforts which secured his father's release "after 1,680 days of captivity."
He added that he will greet Noury at Tehran's Mehrabad airport later on Saturday.
Noury, 63, is a former Iranian prison official who was arrested at Stockholm airport in November 2019 and later sentenced to life in prison after Iranian dissidents in Sweden filed police complaints against him over killings in 1988.
His case relates to the killing of at least 5,000 prisoners across Iran to avenge attacks carried out by the rebel People's Mujahedin of Iran (MEK) at the end of the Iran-Iraq war of 1980-88.
A Swedish court had found Noury guilty of "grave breaches of international humanitarian law and murder" but he had argued he was on leave during the period in question.
Iran condemned the sentence but Sweden insisted the trial was held under its principle of universal jurisdiction, which allows it to try a case regardless of where the alleged offence took place.
Kristersson said Iran had made Floderus and Azizi "pawns in a cynical negotiation game, with the aim of getting Iranian citizen Hamid Noury released from prison in Sweden".
He added that, as prime minister, he had "a special responsibility for the safety of Swedish citizens. The government has therefore worked intensively on the issue, together with the Swedish security service, which has negotiated with Iran."
Kristersson added: "It has been clear all along that the operation would require some difficult decisions. Now we have made those decisions."
Other Swedish citizens are held in Iran including dual national Ahmad Reza Jalali, who is already on death row after he was detained in 2016 and sentenced to death on espionage charges.
The Islamic republic does not recognise dual nationality.
Several other Europeans including from France, Britain, Germany and Austria are still held in Iran.
On Thursday, French citizen Louis Arnaud, 36, returned to Paris after spending more than 20 months incarcerated in Iran on national security charges.
Activists and some Western governments accuse Iran of exercising a strategy of taking foreign nationals as hostages to force concessions from the West.
Last year, Oman helped mediate a swap deal between Iran and the United States, as well as facilitating the release of six European detainees in Iran.