Some 29 people have been injured by an explosion in the Chelsea area of New York City.
Mayor Bill de Blasio said the blast, which went off in 23rd Street on Sixth Avenue at around 9 pm on Saturday, is being treated as "intentional."
However, he stressed there is no evidence of a terrorist connection.
At a news conference he said,
He added, "There is no specific and credible threat against New York City at this time," but confirmed, "This was an intentional act."
The blast ripped out windows and sent glass flying through the area.
Early social media reports claimed it could be heard a number of blocks away.
Police found a second device that is believed to be a pressure cooker hooked up with wires.
New York Police Commissioner James O'Neill said officers found a video of the incident and are investigating.
The explosion is not being linked to the blast in New Jersey earlier that day.
A device went off as runners prepared to take part in a charity race in Seaside Park.
The event had been delayed because of an unattended bag. The bomb went off in a garbage bin and the race was canceled. There were no reports of injury.