An explosion was heard before a fire and collapse at a 3-story building on Manhattan's East Side on Monday, the Fire Department said.
The White House said that the cause of the blast was not terror related.
Television reports said people were trapped inside, but fire officials did not immediately confirm that.
Heavy black smoke rose high above the building, wedged between taller structures on 62nd Street between Park and Madison avenues. Damage, including shattered windows, could be seen at one of the adjoining buildings.