In a deal brokered by Oman, Tehran freed a Belgian aid worker convicted of spying in return for a diplomat jailed for plotting a bomb attack in France. The targets of the thwarted terror attack were Iranian exiles.
The Paris-based National Council of Resistance of Iran (NCRI) said in a statement that the deal between the two countries would "embolden the religious fascism ruling Iran to continue its crimes through repression and regional and international terrorism."
The prisoner swap was agreed despite appeals by dozens of Belgian and international legal and human rights experts.
What do we know about the prisoner swap?
Tehran released Belgian aid worker Olivier Vandecasteele on Thursday night after almost 15 months in custody, Belgian officials said. Vandecasteele was sentenced in January to 40 years and 74 lashes on charges of money laundering and carrying out spying activities with the United States.
He was freed in exchange for Assadollah Assadi, an Iranian diplomat who was jailed in Belgium over a 2018 plot to bomb a meeting of NCRI exiles in France.
Belgian Prime Minister Alexander de Croo said the 42-year-old Vandecasteele had arrived in Oman and would likely arrive back in the country later Friday.
"Olivier spent 455 days in prison in Tehran in unbearable conditions," de Croo said.
Reflecting on the swap, he added: "Olivier's life has always come first. It's a responsibility that I take upon myself, that I accept. In Belgium, we do not abandon anyone."
Iran's foreign minister, Hossein Amir-Abdollahian, tweeted that Assadi, "the innocent diplomat of our country... is now on his way back to his homeland and will soon enter our beloved Iran."
Oman brokers swap under bilateral treaty
The prisoner swap was brokered by Oman, which has good relations with both Iran and Western countries and has acted before as a mediator.
The path was smoothed by a bilateral treaty that took effect last month under which Belgian prisoners in Iran can serve their sentences at home and vice versa.
Oman's Foreign Ministry said: "Those released were transferred from Tehran and Brussels to Muscat today, Friday, in preparation for their return to their countries."
Critics of the pact alleged that it would only encourage Tehran to take Belgians hostage for use as bargaining chips to seek the return of agents like Assadi arrested for terror offenses in the West.
NCRI, the target of the 2018 bomb plot, challenged the treaty in Belgium's constitutional court.
But de Croo's government insisted that the deal was the only way to win Vandecasteele's freedom, and in March the court upheld the treaty.
What was Olivier Vandecasteele accused of?
Vandecasteele was arrested in Iran in February 2022 while packing up his belongings.
He had been working with the Norwegian Refugee Council and Relief International in the Islamic Republic from 2015 to 2021, according to Amnesty International.
In January, he was sentenced to 40 years in prison and 74 lashes for "espionage," as well as money laundering and currency smuggling.
His family and the Belgian government strongly denied Iran's claims, made without evidence, that he was a spy.
Belgium's justice minister said at the time that Vandecasteele's conviction was based on fabricated evidence and amounted to retribution for the prison term given to Assadi.
What was Assadollah Assadi accused of?
In 2021, a court in Antwerp convicted Assadi, an Iranian diplomat in Vienna, of masterminding a thwarted bomb attackagainst an exiled Iranian opposition group in France and sentenced him to 20 years in prison.
Prosecutors tied Assadi to a couple, stopped by the Belgian police and found with 550 grams (1.21 pounds) of TATP explosives and a detonator in 2018.
They had been trying to target a meeting in Villepinte, France, of the Mujahedeen-e-Khalq, an exiled Iranian opposition group known as the MEK.
Among dozens of prominent guests at the rally in Villepinte that day were then-US President Donald Trump's lawyer, Rudy Giuliani; Newt Gingrich, former conservative speaker of the US House of Representatives; and former Colombian presidential candidate Ingrid Betancourt.
Assadi was arrested a day later in Germany and transferred to Belgium.
Belgian intelligence identified him as an officer of Iran's intelligence and security ministry who operated undercover at the Iranian Embassy in Austria.
Does exchange set a precedent?
Iran has detained a number of foreigners and dual nationals over the years, accusing them of espionage or other state security offenses and sentencing them following secretive trials in which rights groups say they have been denied due process.
Critics have repeatedly accused Iran of using such prisoners as bargaining chips with the West.
Earlier this month, Iran released a Frenchman, Benjamin Briere, and a French-Irish citizen Bernard Phelan, but continues to hold two dozen foreigners who Western capitals and families regard as hostages.
Iran, facing Western sanctions over its rapidly advancing nuclear program, hasfaced protests in recent months and economic strain.
Second publication by courtesy of DW