Belgian authorities say they are investigating information suggesting that the Islamic State (IS) group has sent more militants to Europe.
"Signals appear to suggest that IS has again sent fighters to Europe and Belgium," the head of Belgium's security threat analysis center, Paul Van Tigchelt, said on April 19.
He did not elaborate.
But Van Tigchelt said Belgium will remain on its second highest alert level because "the threat is still there; it's serious and possible."
He also said Belgian authorities believe they have "destabilized" the IS network that carried out the March 22 attacks which killed 32 people at the Brussels airport and subway. The perpetrators have been closely linked to the group that carried out November attacks in Paris that killed 130 people.