Belgium on Tuesday launched an investigation into how a Syrian man arrested last week on suspicion of carrying out war crimes for the Islamic State group was granted refugee status.
The 38-year-old, who left Syria in 2015, was detained over the executions of civilians who refused to swear allegiance to the jihadists near the historic city of Palmyra, federal prosecutors told Belga news agency.
The role of the suspect within the jihadist group and whether he participated in the killings in central Syria remains to be determined by an investigation led by Belgian state prosecutors.
"The asylum procedure serves to protect people threatened with war or persecution, not those who are guilty of war crimes," Belgium's Secretary of State for Asylum and Migration Nathalie de Moor said.
De Moor said that if the man was proven to be guilty then he would be stripped of the refugee status granted to him eight years ago.
The civil war in Syria started in 2011 with a brutal crackdown on demonstrators by the government of President Bashar al-Assad before spiralling into a complex conflict involving jihadist groups.
Millions of Syrians have fled the violence for neighbouring countries, with the arrival of a major wave of refugees in the EU in 2015 causing a crisis for the bloc.