Belgian terror police have questioned 15 Muslims after launching a series of early morning raids across the country.
Officers descended on addresses in the Belgian cities of Ghent, Antwerp and Deinze, according to the federal prosecutor.
Of those arrested, four were charged with involvement in terrorism as part of a probe into the financing of terror groups and recruiting terrorists for ISIS.
But the raids were not linked to the deadly Brussels attacks of March 22 in which 32 people were killed, authorities said.
‘Those persons have been indicted for participation in the activities of a terrorist group, amongst others its funding,’ a statement said.
‘Some of them are suspected of recruiting people with a view to departing to Syria and joining Islamic State there,’ it added.
Belgium and much of the rest of Europe has been on edge following a wave of ISIS attacks.
In March this year suicide bombers attacked Brussels Airport and a metro station killing 32 people.
It came just months after Muslim terrorists went on a murderous rampage through Paris, using machine guns and bombs to murder 130 in cafes, bars and at the Bataclan music theatre.
Scores of people were murdered when a Muslim jihadist drove through crowds of people celebrating Bastille Day in Nice.