The ten were arrested during raids in Molenbeek and others areas of the Belgian capital but the case is not linked to the deadly November Paris attacks, the federal prosecutor's office said in a statement.
Several of those involved in the Paris killings came from Molenbeek.
"The raids were carried out as part of an investigation into a recruitment network linked to Islamic State. The investigation helped determine that several people had travelled to Syria to join Islamic State," it said.
Investigators were studying mobile phones and computer equipment seized in a total of nine raids across Brussels.
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Belgium has produced more jihadist fighters relative to its population than any other country in Europe, with some 500 believed to have gone to fight in the Middle East.
Many have joined the Islamic State group which claimed the November attacks on the French capital.
Belgian police are holding several people in connection with the November 13 attacks in Paris which left 130 people dead and hundreds wounded as it emerges that the onslaught was largely organised and coordinated from Belgium.