Belgium's parliament on Wednesday approved a controversial prisoner-swap treaty with Iran in a first reading of a text that still has to be submitted to a full vote to be ratified.
The treaty has been slammed by an Iranian dissident group, the National Council of Resistance of Iran, as well as some US lawmakers and Amnesty International as paving the way for an Iranian diplomat jailed in Belgium on a terrorism conviction to be allowed to return home, said AFP.
Belgian Justice Minister Vincent Van Quickenborne on Tuesday told MPs that unless the treaty was adopted, "the threat to our Belgian interests and certain Belgian citizens will increase".
He said Iran was already "illegally" holding captive a Belgian aid worker, Olivier Vandecasteele, 41, on trumped-up "espionage" charges.
The full parliamentary vote on the treaty, which was signed in March, is expected to take place at the earliest on July 14, pushed back from Thursday this week for procedural reasons.
Tehran also holds a Swedish-Iranian academic, Ahmadreza Djalali, who taught at a Brussels university under the same charges, and has sentenced him to death.
The NCRI and Amnesty say they are the latest foreigners seized by Iran as leverage against Western countries.
The Belgian justice ministry says it is incumbent on Brussels to remove innocent people from the clutches of Iran's "authoritarian regime".
"Our government has the moral duty to be preoccupied about the fate of innocent Belgian hostages. That is my priority right now," Quickenborne said on Wednesday.
Tehran is furious that Belgium last year jailed one of its diplomats, Assadollah Assadi, 50, after he was found guilty of masterminding a thwarted bomb attack on an NCRI event outside Paris in 2018.
Assadi, who was convicted of attempted "terrorist" murder and "participating in the activities of a terrorist group", is serving a 20-year sentence which he declined to appeal.
Attached to Iran's embassy in Austria, he was arrested in Germany where his claim to diplomatic immunity was denied, and extradited to Belgium for his trial.
Belgian authorities had intercepted a car carrying a bomb made from explosives supplied by Assadi as it was on its way to the targeted NCRI event. They were informed by several European intelligence services of the plot.
