‘Intentional’ blast injures 29 in Manhattan, second device found

A powerful explosion caused by what the authorities believe was a homemade bomb injured at least 29 people on a crowded sidewalk in the bustling Chelsea neighborhood of Manhattan on Saturday night.

A few hours later, the authorities found and removed what they described as a second explosive device four blocks away, raising the possibility that two bombs had been planted in the heart of the city.

Mayor Bill de Blasio called the explosion — which occurred about 8:30 p.m. on West 23rd Street — “an intentional act” but initially said there was no connection to terrorism and no immediate claim of responsibility.

Police officers swarmed Chelsea’s streets after 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.” As the authorities sought to identify what had caused the explosion, they described the second device as a pressure cooker resembling the one used in the deadly Boston Marathon bombings in 2013, according to a police official, who spoke on the condition of anonymity to discuss a continuing investigation. 

It was unclear whether the blast on West 23rd Street had been caused by the same type of explosive.

In the immediate aftermath, the police shut down a swath of Manhattan south of Midtown. The area from 14th Street to 32nd Street was closed to traffic between Fifth and Eighth Avenues. But by 7 a.m., only 23rd Street remained closed.