The suspects had been monitored for several days before the arrests on suspicion of being part of a cell that had intention and means to carry out an attack.
“Evidence gathered during the inquiry demanded immediate intervention,” the public broadcaster RTBF cited a statement by the federal prosecutor’s office as saying.
Belgium’s federal ministers were placed under increased security protection amid heightened terror risks, local media reported Saturday.
Late Friday security services acted on a warning from the country’s Coordinating Unit for Threat Analysis (OCAM), the RTBF public broadcaster said. There were no details on the nature of the threat.
According to RTBF, security was stepped up for those in top government jobs — the prime minister, the foreign policy chief, the minister of interior and the main justice official. No additional safety measures for police departments or trade centers were taken.
Belgium raised its terror alert to the highest fourth level following the March terrorist attacks in the Brussels Airport and in the subway that killed 35 people and injured over 300.