Firefighters arrive at the scene of an apparent explosion in Manhattan's Chelsea neighborhood, in New York, Saturday, Sept. 17, 2016. (AP Photo/Andres Kudacki)
Gov. Andrew Cuomo tours the scene the morning after an explosion in Chelsea injured 29 people. (Photo: Gov. Cuomo's office)
FDNY on the scene in Manhattan, New York. (Twitter/@sergeydgr8)
FDNY on the scene in Manhattan, New York. (Twitter/@sergeydgr8)
Firefighters gather as heavily armed police block the area while they search for an explosive device on West 27th street and 7th Avenue in Manhattan, New York, Saturday, Sept. 17. (AP Photo/Andres Kudacki)
Heavily armed police guard the area as they search for an explosive device on West 27th Street and 7th Avenue in Manhattan's Chelsea neighborhood, in New York, early Sunday. (AP Photo/Andres Kudacki)
Gov. Andrew Cuomo tours the scene the morning after an explosion in Chelsea injured 29 people. (Photo: Gov. Cuomo's office)
Heavily armed police guard the area as they search for an explosive device on West 27th Street and 7th Avenue in Manhattan's Chelsea neighborhood, in New York, early Sunday. (AP Photo/Andres Kudacki)
Police work near the scene of an explosion in Manhattan's Chelsea neighborhood, in New York, Saturday, Sept. 17, 2016. (AP Photo/Andres Kudacki)
Mayor Bill de Blasio, center, and NYPD Chief of Department James O'Neill, left, react during a press conference near the scene of an explosion on West 23rd street in Manhattan. (AP Photo/Andres Kudacki)
People try to access the area near the scene of an explosion on West 23rd Street and 6th Avenue in Manhattan's Chelsea neighborhood, in New York, early Sunday, Sept. 18, 2016. (AP Photo/Andres Kudacki)
People try to access the area near the scene of an explosion on West 23rd Street and 6th Avenue as members of the military stand guard in Manhattan's Chelsea neighborhood. (AP Photo/Andres Kudacki)
Passersby are redirected by police officers as the police block the street near the scene of an explosion on West 23rd Street and 6th Avenue in Manhattan's Chelsea neighborhood. (AP Photo/Andres Kudacki)
Police arrive on the scene of an explosion in Manhattan's Chelsea neighborhood, in New York, Saturday, Sept. 17, 2016. (AP Photo/Andres Kudacki)
Police and firefighters work near the scene of an apparent explosion in Manhattan's Chelsea neighborhood, in New York, Saturday, Sept. 17, 2016. (AP Photo/Andres Kudacki)
Gov. Andrew Cuomo tours the scene the morning after an explosion in Chelsea injured 29 people. (Photo: Gov. Cuomo's office)
Mayor Bill de Blasio, center, and NYPD Chief of Department James O'Neill, center right, speak during a press conference near the scene of an apparent explosion on West 23rd Street. (AP Photo/Andres Kudacki)
Police said an explosive device was placed near this dumpster on West 23rd Street, causing it to be moved and mangled. (Photo: @voicehalf / Twitter)
Car windows were shattered after an explosion in New York City's Chelsea neighborhood Saturday, Sept. 17, 2016. (WABC Photo/CeFaan Kim)
FDNY on the scene in Manhattan, New York. (Twitter/@itaycohai)
FDNY on the scene in Manhattan, New York. (Twitter/@TimTeeman)
FDNY on the scene in Manhattan, New York. (Twitter/JK Clarke)
FDNY working on a head injury in Chelsea after an explosion. (Twitter/JK Clarke)
CHELSEA, Manhattan -- The New York City Fire Department responded to the scene of an explosion in Manhattan.