The searches were conducted in Antwerp, Liege and Ghent, and the Brussels region.
ADVERTISEMENTBelgian police have searched 14 houses as part of a terrorism investigation, according to the federal public prosecutor’s office.
According to local media, the operation focused on investigating a group suspected of funding terrorism and planning a terrorist attack.
A statement from the office said seven people have been arrested and brought in for questioning, but they have not yet been charged.
Belgium's terrorist threat level has been set at level three, indicating it is considered "possible and probable," following a terrorist attack in Brussels in October where two Swedish nationals were killed.
Security on high alert ahead of Paris Olympics
The prosecutor's office did not clarify whether the operation was linked to the Paris Olympics, which begins on Friday, although local media reported the timing of the operation was partly linked to the start of the Games.
France has been on high alert over the past few weeks as preparations to host the Olympics hit the final stretch.
On Wednesday prosecutors in Paris said that they had arrested a 40-year-old Russian man at his apartment on suspicion of planning to “destabilise the Olympic Games.”
He was charged with "conducting intelligence work on behalf of a foreign power" with the intention to "provoke hostilities in France," crimes that are punishable by a 30-year sentence in France, according to a statement from the Paris prosecutor’s office.
The 2015 terror attacks in Paris were planned and coordinated in Belgium, and several of the assailants had Belgian nationality. At least 130 people were killed and 368 were wounded in the attack.
One of the main suspects in the Paris attacks trial was later convicted for involvement in a bombing at Brussels Airport in 2016, which killed 34 people.