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Surveillance video shows moment explosion rocked Chelsea neighborhood

CHELSEA, Manhattan — Surveillance video captured the terrifying moment an explosion rocked the neighborhood of Chelsea,  shattering windows and sending people running in the streets.

The video, which shows angles from inside and outside Orangetheory Fitness on 23rd Street, shows a screen laying outside on the street after the explosion and what appears to be papers flying in the air.

The explosion injured 29 people — all have been released from the hospital.

Police are scouring the area for evidence Sunday as they tried to pinpoint exactly what — and who — caused the blast.

“A bomb exploding in New York is obviously an act of terrorism,” Gov. Andrew Cuomo told reporters Sunday, vowing that authorities will catch whoever is responsible.

The governor said there’s no evidence of an international terrorism link to Saturday’s blast, which shook New York City’s Chelsea neighborhood and sent panicked people scrambling for cover.

“A bomb going off is generically a terrorist activity. That’s how we’ll consider it. And that’s how we will prosecute it,” he said.

Cuomo cautioned that the investigation remains in its early stages and added that no terror group had taken responsibility for the explosion.

In light of the blast, he said 1,000 additional New York State Police officers and National Guard troops will be deployed to patrol bus terminals, airports and subway stations.

The stepped-up security is “just to err on the side of caution,” Cuomo said. “I want New Yorkers to be confident when they go back to work on Monday that New York is up and running and we’re doing everything that we need to do.”

CNN contributed to this report.