Brussels has confirmed that Iran has been holding a Belgian man for the past four months under “espionage” charges as it weighed a controversial prisoner swap treaty with Tehran.

Belgium’s Justice Minister Vincent Van Quickenborne said Tuesday the man was seized in Iran on February 24 and has been in “illegal” detention since. 

He did not identify the man but he was most likely referring to Olivier Vandecasteele, a 41-year-old Belgian aid worker who has served in various international humanitarian organizations since at least 2006.

The announcement by the ministry came after Iran International revealed the identity of the Belgian national, who had previously worked in India, Afghanistan, and Mali and later became the director of Norwegian Refugee Council’s Iran operations in 2015 and assumed the same position with Relief International in Iran in 2020. On July 2, an informed source had told Iran International that at least two Belgian citizens are currently in prison in Iran.

A draft law proposed by the Belgian government to the parliament could put the seal of approval on an agreement with Iran, which could lead to the release of Assadollah Assadi, an Iranian diplomat serving a 20-year prison sentence in Belgium for planning a terror attack in Paris four years ago.

Numerous people and groups from around the world have warned about the imminent perilous consequences of the prisoner exchange treaty, calling “the green light to state terrorism” that only emboldens the Islamic Republic.