Major police operation underway in Brussels

An explosion was heard during a police search of a house in Brussels borough of Schaerbeek, Belga news agency said on Friday.

The house search in Schaarbeek is part of an ongoing investigation following multiple bombing attacks which killed at least 31 people and wounded 316.

Belgian media is also reporting that a man was "neutralized" by police during the raid.

Police sources told AFP that the anti-terror raid is linked to Thursday's arrest of a man who was plotting a terror attack in France.

Witnesses are tweeting about the explosion and sharing photos of the scene. 

Belgian national Ibrahim el Bakraoui and his brother, Khalid el Bakraoui, are believed to have detonated suicide bombs at Brussels airport and Maelbeek metro station on Tuesday morning. The third bomber is believed to be ISIS bomb maker Najim Laachraoui, who is also thought to have died in the attack.

Police are still searching for, and have yet to identify, the man on the far right of an image captured by the airport's CCTV footage.

Belgian Federal Police

This is a developing story.