New York Mayor Bill de Blasio says eight people have been killed when a pickup truck drove onto a bike path in Lower Manhattan on October 31.
De Blasio said that “over a dozen more” people were injured in what he called " a particularly cowardly act of terror aimed at innocent civilians."
Eleven people had serious but not life-threatening injuries, according to emergency services.
Police said a vehicle rented from retailer Home Depot struck down bicyclists and pedestrians before crashing into a school bus. The driver -- described as a 29-year-old man – then got out wielding what they said were fake guns.
The man was shot and detained by police officers. His identity and condition were not immediately disclosed.
"In NYC, looks like another attack by a very sick and deranged person," President Donald Trump tweeted. "Law enforcement is following this closely. NOT IN THE U.S.A.!"
New York Governor Andrew Cuomo described it as a "lone wolf" attack, saying there is no evidence to suggest it was part of a "wider plot or wider scheme."