Police said an explosion has torn through three adjacent homes in Belgium's northern port town of Antwerp and injured up to 20 people.

Antwerp police said in a statement late Monday that most of the injuries were slight. Authorities rescued seven people from under the rubble.

Antwerp police spokesman Wouter Bruyns told VRT network: "There are about 10, a maximum 20 casualties, fortunately including many slightly injured."

The explosion ripped through the homes late in the evening. Antwerp police quickly announced that the blast was not part of a terror attack.

At least one building totally collapsed. Rescue workers were still going through the debris around midnight.