WEB DESK /

new-york-cityAt least 29 people have been injured in an explosion in New York City today. Officials say fire trucks and ambulances converged on the scene after what witnesses described as a deafening blast in the Chelsea district of Manhattan. A local official told US media FBI and Homeland Security officials are at the scene. The cause of the explosion is unclear.

The New York Fire Department said none of the injuries appear to be life threatening. The explosion comes just hours after a pipe bomb exploded in a New Jersey town, shortly before thousands of runners were to participate in a charity race nearby. No injuries were reported in the New Jersey blast.

Mayor Bill de Blasio called the explosion “an intentional act” but initially said there was no connection to terrorism. He cautioned that the authorities had just begun their investigation into the blast, which reverberated across a city scarred by terrorism and vigilant about threats just days after the 15th anniversary of the Sept. 11 attacks.

“Whatever the cause,” Mr. de Blasio said, “New Yorkers will not be intimidated.”

According to New York Times, the explosion’s aftermath prompted the shutdown of a wide swath of Manhattan south of Midtown. The Police Department said at 1:15 a.m. that 14th Street to 32nd Street was closed to traffic between Fifth and Eighth Avenues until further notice.

A grim Mr. de Blasio, speaking at a news conference at the scene, said “injuries are significant.” But for the moment, he said, none of them were life-threatening.

Many of the injuries were caused by shrapnel from the explosion, which witnesses said seemed to have come from a sidewalk Dumpster on West 23rd Street near the Avenue of Americas. Images of a twisted Dumpster in the middle of 23rd Street quickly proliferated on Twitter.