Authorities were treating the incident as a terrorist attack and were taking the lead in the investigation, a senior law enforcement official said, The New York Times reported.
Two law enforcement officials said that after the attacker got out of the truck, he was heard yelling, "Allahu Akbar" -- "God is great".
The man drove down a bike path beside the Hudson River in Lower Manhattan before he crashed his pickup truck, jumped out with fake guns and was shot by police officers
Mayor Bill de Blasio said at a news conference: "Based on information we have at this moment, this was an act of terror, and a particularly cowardly act of terror aimed at innocent civilians."
Two law enforcement officials said the driver of the truck, a 29-year-old man who came to the US in 2010, was in grave condition. One official said he had rented the truck in New Jersey.
The motorist hit numerous people as nearby Stuyvesant High School was letting out for the day, officials said. At least 15 people were injured, but officials were still working to assess the extent of the casualties.
"He jumped out of the truck with a pellet gun, yelled, 'Allahu Akbar,' and the First Precinct lit him up," a law enforcement official said, referring to a police officer who had been on post nearby and whom the authorities credited with saving lives.
Witnesses described gunshots ringing out, people scrambling for cover and a street strewn with bodies and crumpled bicycles.
The driver, who was shot several times, was being treated at a nearby hospital. He had crashed the truck into a school bus. It was unclear if anyone was on the bus. The police said they were not looking for additional suspects.
A large section of the West Side Highway was closed for the investigation as hundreds of officers, including the bomb squad, responded to the scene. The truck came to a rest near Chambers Street, facing eastbound.
Students at Stuyvesant High School reported that they saw a man shooting from a pickup truck, and then saw the truck turn and strike a school bus.
IANS