Explosion in New York’s Chelsea neighborhood

People stand behind police lines as firefighters, emergency workers and police gather at the explosion scene in Manhattan.

Police stand guard near the scene of an explosion in Manhattan’s Chelsea neighborhood.

Members of the FBI search for evidence at the scene of the Chelsea explosion.

Police and firefighters respond to an explosion in New York’s Chelsea neighborhood.

Firefighters arrive at the scene of an explosion in Manhattan’s Chelsea neighborhood.

Bystanders watch as police, fire crews and other first responders work at the explosion scene in New York’s Chelsea neighborhood.

Police, firefighters and other emergency workers respond to the scene of an explosion in New York’s Chelsea neighborhood.

Witness Deborah Griffiths describes the scene on West 23rd Street after the explosion.

New York Mayor Bill de Blasio, center, speaks at a press conference after the Chelsea explosion.