Police officers and federal agents were scouring the streets with flashlights, robots and dogs to ensure there were no other devices in the area.
New York City Mayor Bill de Blasio told reporters early indications are that the explosion at 23rd Street and 6th Avenue in Manhattan that injured 29 “was an intentional act.”
Investigators believe the blast was caused by an explosive device in or near a dumpster, a law enforcement source told CNN.
Police have video from businesses on the street where the explosion occurred, which could yield key details about the hours before the attack.
Investigators are looking at surveillance video appearing to show a person near where the explosion at the 23rd street location occurred, according to a local and federal law enforcement official.
Investigators are trying to determine if that individual is connected to the explosion.
De Blasio says “there is no evidence at this point of a terror connection” and there is no “credible and specific threat” to New York City.
Police have increased security across the five boroughs as a precaution, a law enforcement source told CNN.
Ambulances arriving at some local hospitals were being checked by armed guards.
24 people were taken to the hospital after the explosion, but “none of those injured are likely to die,” the mayor says.
De Blasio says they also believe there is no specific connection to an earlier incident in New Jersey, where an explosion went off in a garbage can on the route of a Marine Corps charity run.