Watch fireball on New York skyline

As Superstorm Sandy made landfall along the eastern seaboard in the US, there were reports of an explosion at a substation in Manhattan.

At least 660,000 people in New York had lost power because of the explosion and a planned power shut-down.

Authorities said the exact cause of the blast was not known, but suspected that flood waters or flying debris could have been involved.

A video of the explosion showed a large fireball light up the New York skyline on the East Side. (Courtesy: YouTube)