Former Belgium international Radja Nainggolan has been arrested as part of an investigation into cocaine trafficking into Europe from South America, the Brussels public prosecutor's office said.
Brussels federal police carried out 30 searches on Monday morning, mainly in the province of Antwerp and in and around Brussels as part of the investigation.
The Brussels public prosecutor's office confirmed that the player was "deprived of his liberty in connection with this case."
The probe focuses on the alleged importation of cocaine from South America via the port of Antwerp, and its redistribution in Belgium, the office said.