An investigation is underway as to what caused an explosion on Portland’s touristy Exchange Street Sunday afternoon.

The Portland Fire Department says the cover blew off a CMP electrical vault, which sent bricks on a sidewalk flying.

There were no reports of any injuries or damage to any nearby buildings.

The intersection of Middle and Exchange Streets was closed to traffic during an investigation from fire and city crews.

Central Maine Power was on the scene as well, and some CMP customers may have lost power. The explosion took place before 1pm Sunday.

This is a developing story.