Belgian authorities say they have arrested a man on suspicion that he was part of a terrorist group and might have been planning an attack.

Federal prosecutors said Monday the 22-year-old Belgian man, identified as Jimmy K., is charged with "taking part in the activities of a terrorist group."

Searches were conducted in three Belgian towns in connection with the arrest but no weapons or explosives were found. No other details were provided.

State broadcaster RTBF says the man was detained early Sunday at his grandmother's house in Wavre, 30 kilometers (19 miles) southeast of the capital, Brussels. It said he had converted to Islam and become radicalized and was in the early stages of preparing an attack. RTBF did not identify the source of its information.