Massive explosion in New York City levels apartment building

A massive explosion has sparked a fire and a building collapse in New York City's upper east side.

The blast occurred about 9:00 a.m. Eastern Time Wednesday morning near 116th and Park Avenue in what is commonly called East Harlem in Manhattan.

The Metro North rail line has been suspended along Park Avenue, apparently due to debris on the tracks from the explosion.

KRMG's Todd Starnes is in New York City, and tells KRMG the building is apartments, several stories tall but not a high-rise.

The area is primarily residential, Starnes said, and not generally visited by tourists.

At approximately 10:30 a.m. Eastern Time, FDNY called for a fourth alarm to bring additional assets to bear on the situation.

The investigation into the cause of the explosion will begin when the fire is brought under control.

Early accounts from witnesses and rescue agencies indicate that at least a dozen people so far have been treated for injuries.