Iran freed a Belgian aid worker imprisoned in Tehran for 455 days on charges of spying, in exchange for Belgium releasing a former Iranian diplomat who was convicted in 2021 of a thwarted bomb plot, officials from both countries said on Friday.
The aid worker, Olivier Vandecasteele, was flown late Thursday from Tehran to Muscat, the capital of Oman, where the exchange took place, Belgium’s prime minister, Alexander De Croo, said on Friday.
“At this moment our compatriot Olivier Vandecasteele is on his way to Belgium,” Mr. De Croo said in a video address from Brussels, confirming that the government had secured Mr. Vandecasteele’s release. He added that Mr. Vandecasteele had undergone medical examinations to assess his health after more than a year “under very difficult conditions.”
Mr. Vandecasteele had worked in Iran for five years until he lost his job in March 2021 and left the country. When he returned to retrieve some belongings in February of last year, he was arrested by Iranian authorities, who sentenced him to 40 years in prison and 74 lashes on charges of espionage, money laundering and currency smuggling. The Belgian government had called Mr. Vandecasteele’s imprisonment arbitrary and said Iran had provided no information on the case.
In exchange for Mr. Vandecasteele being freed, Oman negotiated the release of Assadollah Assadi, an Iranian diplomat who was arrested in Germany in 2020 on accusations of plotting a bomb attack at a meeting of Iranian opposition leaders in France in 2018. The attack was thwarted, but he was later convicted in Brussels in 2021 and sentenced to 20 years in prison.
Photos posted late Friday by Mizan, a news agency overseen by Iran’s judiciary, appeared to show that Mr. Assadi had arrived in Tehran.
In a statement posted to Twitter earlier on Friday, Iran’s foreign minister, Hossein Amir-Abdollahian, thanked the Omani government for brokering the exchange and sending Mr. Assadi, “the innocent diplomat of our country, who was illegally detained in Germany and Belgium for more than two years against international law” back to Iran.
Belgium’s Parliament approved a much-criticized treaty with Iran in July of last year that allowed for prisoner exchanges between the two countries. Critics of the treaty said that the country was surrendering to a form of blackmail from Iran, which puts foreigners more at risk of being taken hostage.
On Friday, Belgian authorities said they had not used the treaty in negotiating Mr. Vandecasteele’s release, according to the Belga news agency. Still, analysts say, Iran has made a practice of using Westerners as pawns.
“This has been a consistent policy by the Iranian government for decades, to use hostage-taking of foreign nationals and dual nationals for its foreign policy goals,” said Hadi Ghaemi, the executive director of the Center for Human Rights in Iran, which is based in New York. “Unfortunately this continues to work for them,” he added, noting that each prisoner swap “only encourages the Iranian Revolutionary Guards to take more hostages.”
In a statement on Friday, Amnesty International applauded Mr. Vandecasteele’s release but said it was “deeply disturbed” by an exchange deal that only perpetuated a “climate of impunity for the extraterritorial targeting of Iranian dissidents for extrajudicial executions, torture, and other ill-treatment.”
Kylie Moore-Gilbert, a British-Australian scholar, was freed in a 2020 exchange for three Iranian men who were imprisoned in Thailand for organizing a foiled plot to assassinate Israeli diplomats in 2012.
Earlier this month, Iran released two French citizens, Benjamin Brière and Bernard Phelan, after they had been charged with spying. Nazanin Zaghari-Ratliffe, a British-Iranian, was freed in March after being detained for 6 years as a diplomatic pawn, according to her family.
Mr. Ghaemi noted that the latest exchange had taken place against the backdrop of a surge in executions in the country. At least 209 people have been put to death since January, according to the United Nations.
More than two dozen foreign and dual nationals are still detained in Iranian prisons.
Koba Ryckewaert and Leily Nikounazar contributed reporting.