NEW YORK – Authorities in New York said that dozens of people were injured in an explosion Saturday night in the Chelsea neighborhood of Manhattan.

At least 29 people suffered non-life-threatening injuries, according to the New York Police Department.

Police officers, firefighters and other first responders rushed to the blast scene, which closed a major roadway, forced people out of nearby buildings and brought onlookers to the area.

New York Mayor Bill de Blasio said Saturday night that in the initial hours after the explosion, authorities had found “no evidence at this point of a terror connection to this incident.”

De Blasio said at a news briefing that the explosion was “an intentional act,” but he said during a briefing before 11:30 p.m. on Saturday that little other information was available because the investigation was in its early stages.

“The exact nature and cause of this explosion has not yet been determined,” James O’Neill, the New York police commissioner marking his first day in the position, said at the news conference late Saturday. O’Neill did say that natural gas had been ruled out as a possible cause.

The New York Police Department’s counterterrorism bureau said it was responding to the explosion, which came hours after a pipe bomb exploded in a Jersey Shore garbage can shortly before a scheduled charity race there benefiting Marines and Navy sailors. De Blasio said authorities had not found anything connecting the Chelsea and New Jersey incidents.

In addition, the FBI said it was involved in the response and the Bureau of Alcohol, Tobacco, Firearms and Explosives said its arson and explosives task force was being dispatched to the explosion scene.

Police in New York also said shortly after 11 p.m. that they had found “a possible secondary device” a few blocks away from the explosion scene.