A Spanish judge has issued European Arrest Warrants (EAW) for sacked Catalan leader Carles Puigdemont and four of his allies who went to Belgium, BBC reports.
The five failed to attend a high court hearing in Madrid on Thursday when nine other ex-members of the regional government were taken into custody.
One of those detained has been freed on bail of €50,000 (£44,000; $58,000).
They all face charges of rebellion, sedition and misuse of public funds for pursuing Catalan independence.
Puigdemont declared he would not return to Spain unless he receives guarantees of a fair trial.
A spokesman for the state prosecutor of Belgium noted that they will "study" the warrant.