A Belgian court has ruled that a man charged with participating in a terrorist group and planning to kill people will be kept behind bars for another month as investigation of the case continues.

The Belgian Federal Prosecutor's Office said in a statement that a judge in Liege issued the ruling on Wednesday affecting the 33-year-old suspect, identified as Nourredine H.

He and his brother, Hamza H., were taken into custody following house searches in Liege and the Mons area on Friday. The brother has been released.

Prosecutors have not divulged details of what Nourredine H. is suspected of having planned, but have said the case was not connected to the suicide bombings claimed by the Islamic State group that killed 32 people in Brussels on March 22.