Police and fire officials are on the scene of an explosion and partial building collapse at 116th Street and Park Avenue in Upper Manhattan Wednesday morning.

At least 11 injuries were reported, and Harlem Hospital has one patient with heavy trauma and is expecting at least one more.

East Harlem residents reported hearing a large explosion in the six-story apartment building around 9:30 a.m.

A fourth-alarm fire was burning, and the structural integrity appeared to be compromised. Witnesses reported seeing what appeared to be at least a partial roof collapse.

Smoke poured from the top of the building, and huge amounts of debris littered the surrounding sidewalks and elevated tracks in the area. Windows of buildings in the area were blown out by the force of the blast, and the fire may have spread to other structures as well. Firefighters were dousing the site with water from ladder trucks.

Police called a Level 2 mobilization for crowd control. Con Edison was also responding to shut off the gas.

It is unknown if the building was occupied, but neighbors say it sits between two residential buildings.

The cause of the explosion is unknown at this time.

Metro North New Haven Line service into and out of Grand Central Terminal is temporarily suspended until further notice. Bus service is also affected, with M1, M102 and M116 buses being detoured.