At least one building collapsed after an explosion rocked the Paardenmarkt area in Antwerp on Monday night. The explosion at the Italian restaurant Primavera was so powerful that it caused damage to three buildings.

Police said on Twitter that “multiple victims” were injured in the blast. Local media reports that at least five people have suffered injuries while more victims might be trapped under the rubble.

Emergency rescue teams were dispatched to the scene. Antwerp police believe the incident is not a terrorist act.

Authorities have launched an investigation into the cause of the blast, which happened shortly after 9:30pm local time. With terrorism ruled out, the incident was most likely caused by a gas explosion.