AMERICA WAS on high alert today after a series of knife and bomb attacks of which at least one was claimed by Islamic State.
Some 29 people were injured - one seriously - when a bomb exploded in the fashionable Chelsea district of Manhattan.
No-one claimed responsibility for that incident, but earlier a man was shot dead by an off-duty police officer after wounding eight people in a shopping mall in Minnesota on Saturday.
IS-linked media claims the Minnesota mall stabber was a “soldier of the Islamic State”.
Mayor of New York Bill de Blasio ruled out any terror connections to the Manhattan blast but called the explosion on Saturday night an “intentional act”.
“New York City experienced a very bad incident,” Mr de Blasio said. “We have no credible and specific threat at this moment.”
He tried to calm any fears among nervous New Yorkers, saying the explosion had no terrorist connection and was not related to a pipe bomb explosion earlier Saturday in New Jersey that forced the cancellation of a charity run.
“Now, I want to be clear - whatever the cause, whatever the intention here, New Yorkers will not be intimidated,” the mayor said. “We are not going to let anyone change who we are or how we go about our lives.”
The explosion happened in Chelsea, a residential neighbourhood on Manhattan’s west side known for its art galleries and large gay population.
It was unclear who was behind the blast and what motivated it.
A law enforcement official said a second device that officers investigated four streets from the scene appeared to be a pressure cooker attached to wiring and a mobile phone. The official said the device was found inside a plastic bag, it was removed with a robot and taken to a department firing range in the Bronx.
investigation into the Manhattan explosion came as world leaders descended on the United Nations for a meeting today to address the refugee crisis and the Syrian conflict.