Heavily armed police stand guard near the scene after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people Tuesday, Oct. 31, 2017, in New York. (AP Photo/Andres Kudacki)
Heavily armed police stand guard near the scene after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people Tuesday, Oct. 31, 2017, in New York. (AP Photo/Andres Kudacki)
The scene of a deadly incident along a bike path near Stuyvesant High School in New York. Picture: Bebeto Matthews/AP
The scene of a deadly incident along a bike path near Stuyvesant High School in New York. Picture: Bebeto Matthews/AP
In this still image taken from video, police and ambulances respond to report of gunfire a few blocks from the World Trade Center in New York. AP Photo
In this still image taken from video, police and ambulances respond to report of gunfire a few blocks from the World Trade Center in New York. AP Photo
Firemen work at the scene after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people in New York. Picture: Andres Kudacki/AP
Firemen work at the scene after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people in New York. Picture: Andres Kudacki/AP
A New York Police Department officer stands next to a body covered with a white sheet near a mangled bike along a bike path in New York. Picture: Bebeto Matthews/AP
A New York Police Department officer stands next to a body covered with a white sheet near a mangled bike along a bike path in New York. Picture: Bebeto Matthews/AP
A New York Police Department officer stands next to a body covered with a white sheet near a mangled bike along a bike path in New York. Picture: Bebeto Matthews/AP
A New York Police Department officer stands next to a body covered with a white sheet near a mangled bike along a bike path in New York. Picture: Bebeto Matthews/AP
Emergency personnel carry a man into an ambulance after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people in New York. Picture: Andres Kudacki/AP
Emergency personnel carry a man into an ambulance after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people in New York. Picture: Andres Kudacki/AP
Authorities stand near a damaged Home Depot truck after a motorist drove into a bike path near the World Trade Center memorial, striking and killing several people. Picture: Bebeto Matthews/AP
Authorities stand near a damaged Home Depot truck after a motorist drove into a bike path near the World Trade Center memorial, striking and killing several people. Picture: Bebeto Matthews/AP
Families carry their children out of the scene after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people in New York. Picture: Andres Kudacki/AP
Families carry their children out of the scene after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people in New York. Picture: Andres Kudacki/AP
Emergency personnel carry a man into an ambulance after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people. Picture: Andres Kudacki/AP
Emergency personnel carry a man into an ambulance after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people. Picture: Andres Kudacki/AP
Emergency personnel transport a man on a stretcher after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people. Picture: Mark Lennihan/AP
Emergency personnel transport a man on a stretcher after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people. Picture: Mark Lennihan/AP
In this still image taken from video, police and ambulances respond after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck and killed several people. AP Photo
In this still image taken from video, police and ambulances respond after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck and killed several people. AP Photo
Bicycles and debris lay on a bike path after a motorist drove onto the path near the World Trade Center memorial, striking and killing several people in New York. Picture: Craig Ruttle/AP
Bicycles and debris lay on a bike path after a motorist drove onto the path near the World Trade Center memorial, striking and killing several people in New York. Picture: Craig Ruttle/AP
Bicycles and debris lay on a bike path after a motorist drove onto the path near the World Trade Center memorial, striking and killing several people. Picture: Craig Ruttle/AP
Bicycles and debris lay on a bike path after a motorist drove onto the path near the World Trade Center memorial, striking and killing several people. Picture: Craig Ruttle/AP
Authorities respond near a damaged school bus in New York. A motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people on Tuesday police and witnesses said. Picture: Mark Lennihan/AP
Authorities respond near a damaged school bus in New York. A motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people on Tuesday police and witnesses said. Picture: Mark Lennihan/AP
Authorities stand near a damaged Home Depot truck after a motorist drove into a bike path near the World Trade Center memorial, striking and killing several people in New York. Picture: Bebeto Matthews/AP
Authorities stand near a damaged Home Depot truck after a motorist drove into a bike path near the World Trade Center memorial, striking and killing several people in New York. Picture: Bebeto Matthews/AP
Firemen work in the scene after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people in New York. Picture: Andres Kudacki/AP
Firemen work in the scene after a motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people in New York. Picture: Andres Kudacki/AP

New York - A man driving a rented pickup truck mowed down pedestrians and cyclists on a bike path alongside the Hudson River in New York City on Tuesday, killing eight people and injuring about a dozen others in what authorities said was an act of terrorism.

The 29-year-old suspect was shot by police in the abdomen and arrested after he crashed the truck into a school bus and fled his vehicle, authorities said.

CNN and The New York Times, each citing law enforcement sources, reported that investigators found a note left by the suspect claiming he carried out the attack in the name of the Islamic State militant group.

A US law enforcement source told Reuters the suspect was an Uzbekistan-born immigrant.

The incident marked the greatest loss of life from a suspected terrorist attack in New York since suicide hijackers crashed jetliners into the Twin Towers of the World Trade Center in lower Manhattan on September 11, 2001, killing more than 2 600 people.

Tuesday's assault, on the far west side of lower Manhattan a few blocks from the site of the World Trade Center, was reminiscent of several deadly vehicle attacks in Europe during the past 15 months.

Read: BREAKING: Several killed by vehicle on New York City bike path

"This was an act of terror, and a particularly cowardly act of terror, aimed at innocent civilians, aimed at people going about their lives who had no idea what was about to hit them," Mayor Bill de Blasio told a news conference following the attack.

A spokesperson for the US Department of Homeland Security similarly called the incident an "apparent act of terrorism."

Governor Andrew Cuomo said the suspect appeared to have acted alone.

"There's no evidence to suggest a wider plot or a wider scheme. These are the actions of one individual meant to cause pain and harm and probably death," Cuomo said at the news conference.

Later, asked by CNN in an interview whether the suspect had been known to authorities before the attack, Cuomo replied, "It's too early to give you a definitive answer."

New York City Police Commissioner James O'Neill declined to publicly identify the driver. But a source familiar with the investigation told Reuters the driver's name was Sayfullo Saipov.

CNN and NBC News reported that he entered the United States in 2010.

JOINT TASK FORCE INVESTIGATING

Multiple media outlets, including CNN, reported that the suspect shouted "Allahu Akbar" - Arabic for "God is greatest" - when he jumped out of his truck, citing police officials.

Asked about that at the news conference, O'Neill would only say that an unspecified comment by the suspect when he exited his truck, and the general circumstances of the assault, led investigators to label the incident a "terrorist event."

The Federal Bureau of Investigation joined the New York City Police Department and other agencies in a Joint Terrorism Task Force to conduct a probe of the attack, the FBI said in a statement.

ABC News reported that Saipov lived in Tampa, Florida. A check of court records related to a traffic citation that Saipov received in eastern Pennsylvania in 2015 show he listed addresses then in Paterson, New Jersey, and Cuyahoga Falls, Ohio.

According to O'Neill, the suspect drove onto the bike path in lower Manhattan at 3:05 p.m. He said the man was carrying a paintball gun and a pellet gun.

Two children and two adults were injured when the truck ploughed into the school bus, he said.

O'Neill said the pickup truck driven by the suspect had been rented from the Home Depot hardware chain, but declined to say where it was rented.

After the attack, mangled and flattened bicycles littered the sunlit bike path, which runs parallel to the West Side Highway along the Hudson River.

Of the eight people killed, six were pronounced dead at the scene and two more were pronounced dead at a nearby hospital, O'Neill said.

Fire Commissioner Daniel Nigro said 11 survivors with serious but non-life-threatening injuries were taken to hospitals.

Despite the attack, thousands of costumed Halloween revellers turned out hours later for New York City's main Halloween parade, which went on as scheduled Tuesday night, just a few blocks from the scene of the carnage, with a heightened police presence.

U.S. President Donald Trump was briefed on the incident, White House spokeswoman Sarah Sanders said.

Trump, who has pressed for a ban on travellers entering the United States from some predominantly Muslim countries, said on Twitter that he had ordered Homeland Security officials to "step up our already Extreme Vetting Program. Being politically correct is fine, but not for this!"

In an official White House statement later, the president said, "Our thoughts and prayers are with the victims of today's terrorist attack in New York City and their families." He also paid tribute to the "first responders who stopped the suspect and rendered immediate aid to the victims."

Similar attacks in Europe last year killed dozens of people.

On July 14, 2016, a suspect drove a large truck into a crowd celebrating Bastille Day in the French city of Nice, killing 86 people and injuring hundreds more in an attack for which Islamic State claimed responsibility.

Five months later a Tunisian asylum seeker, who had pledged allegiance to Islamic State, ploughed a truck into a crowded Christmas market in central Berlin, killing 12 people and injuring 48.

On August 17 of this year, a driver rammed his van into crowds in the heart of Barcelona, killing 13 people, in an attack authorities said was carried out by suspected Islamist militants.