Belgian authorities say they are investigating information that suggests the Islamic State group has sent more fighters to Europe, the Associated Press reports.

Paul Van Tigchelt, the head of Belgium's security threat analysis center, says Tuesday that "signals appear to suggest that IS has again sent fighters to Europe, to our country." He did not elaborate.

Van Tigchelt says Belgium will remain on its second highest alert level because "the threat is still there, it's serious and possible."

He says Belgian authorities believe they have "destabilized" the network that carried out the March 22 suicide attacks on the Brussels airport and subway. The perpetrators have been closely linked to the group that carried out the attacks in Paris on November 13.