The fire that ravaged Notre Dame Cathedral in Paris was likely caused by an electrical short-circuit, a French judicial police official told the Associated Press.

The official, whose identity was kept under wraps, said investigators still can't access the Cathedral to examine the fire scene for safety reasons.

Wooden planks are still set up to support some fragile parts of the walls, he noted.

A judicial source also told CNN that no hypothesis is being excluded, adding that investigators are examining all lines of inquiry.