The two minors were placed in a youth protection center. According to Belgian television station RTBF, the suspects had recorded a video of allegiance to the Islamic State and were suspected of planning a stabbing attack on police officers.
The arrests came ahead of Monday’s attack in Vienna, where a man who had previously tried to join Isis went on a rampage in the Austrian capital and killed four people before being killed by police.
Four years ago, coordinated attacks killed 32 people and injured hundreds more at Zaventem airport in Brussels and in the city’s metro. Belgian authorities have since thwarted several terrorist plots.