Belgian authorities have detained four suspects during an anti-terror sweep linked to the recruitment of potential jihadis to go fight in Syria.

Police searched 22 homes mostly in northeastern Belgium early Friday but found no weapons, explosives or ammunition.

The federal prosecutor's office said in a statement the sweep was aimed at "uncovering the organization behind the recruitment and sending" of individuals to Syria.

It stressed the operation was not linked to the Paris attacks of early this month nor to the Jan. 15 operation in and around the eastern town of Verviers, when authorities claimed they prevented an imminent and major terror attack on police.