One person was wounded and detained in a major police operation in the northern Brussels borough of Schaerbeek, Belgian public broadcaster RTBF quoted the local mayor as saying.
Bernard Clerfayt said the person was linked to bomb attacks in Brussels and to a foiled plot this week near Paris.
Heavily armed police and military with trucks cordoned off an area around a major intersection and three blasts were heard which Clerfayt said were controlled explosions.
Broadcaster RTL quoted a witness as saying police approached a person at a bus stop and asked the person to remove a jacket.
“No doubt to check if the person had an explosives belt strapped on,” the witness told RTL. The witness said it was not clear if the person had been wounded, but was lying on the ground and talking to the police.
RTBF cited unidentified sources saying the person arrested had not responded to police orders and had been found to be in possession of a suitcase containing explosive substances.