A man in a rented pickup truck mowed down pedestrians and cyclists along a busy bike path near the World Trade Center memorial in New York City on Tuesday, killing at least eight and seriously injuring 11 in what the mayor called "a particularly cowardly act of terror."

The driver was shot in the abdomen by police after jumping out of the truck with what turned out to be a fake gun in each hand and shouting what witnesses said was "Allahu akbar," Arabic for "God is great," authorities said. The man underwent surgery and was in critical condition but was expected to survive.

Emergency personnel were stationed outside the scene of the deadly attack Tuesday night. New York City officials say eight people were killed after a truck slammed into people on a bike path. (Kena Betancur/Getty Images)

Officials who were not authorized to discuss the investigation and spoke on the condition of anonymity identified the attacker as 29-year-old Sayfullo Saipov and said he is from Uzbekistan and came to the U.S. legally in 2010. He has a Florida driver's licence but may have been staying in New Jersey, they said.

The ride-hailing service Uber confirmed late Tuesday night that Saipov was one if its drivers. The company said he passed a background check and had been actively driving on the platform for more than six months. He has since been banned from the Uber app.

"We are horrified by this senseless act of violence," the company said in a statement. "Our hearts are with the victims and their families. We have reached out to law enforcement to provide our assistance."

The driver barrelled along the bike path in a rented Home Depot truck for the equivalent of about 14 blocks, or around 1.2 kilometres, before slamming into a small yellow school bus. The mayhem and the burst of police gunfire set off panic in the neighbourhood and left the pavement strewn with mangled bicycles and bodies that were soon covered with sheets.

'I saw a lot of blood'

"I saw a lot of blood over there. A lot of people on the ground," said Chen Yi, an Uber driver.

Eugene Duffy, a chef at a waterfront restaurant, said, "So many police came, and they didn't know what was happening. People were screaming. Females were screaming at the top of their lungs."

NY officials say 8 are dead after driver slams into crowd on bike path 0:25

Police closed off streets across the western edge of lower Manhattan along the Hudson River, and officers rushed into the neighbourhood just as people were preparing for Halloween festivities, including the big annual parade through Greenwich Village.

A police bomb squad scoured the truck but found no explosives.

'This was an act of terror'

"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 said.

New York and other cities around the globe have been on high alert against attacks by extremists in vehicles. The Islamic State in Iraq and Syria group (ISIS) has been exhorting its followers to mow down people, and England, France and Germany have seen deadly vehicle attacks in the past year or so.

forensic teams at scene of New York attack <a href="https://t.co/ZGUQ22u9or">pic.twitter.com/ZGUQ22u9or</a> —@cbcsteve

New York Gov. Andrew Cuomo called it a "lone wolf" attack and said there was no evidence to suggest it was part of a wider plot.

The city's police commissioner, James O'Neill, said a statement the driver made as he got out of the truck and the method of attack led police to conclude it was a terrorist act.

'NOT IN THE U.S.A.!'

On Twitter, U.S. President Donald Trump called it "another attack by a very sick and deranged person" and declared, "NOT IN THE U.S.A.!"

In NYC, looks like another attack by a very sick and deranged person. Law enforcement is following this closely. NOT IN THE U.S.A.! —@realDonaldTrump

While police did not specifically blame ISIS for the New York bloodshed, Trump railed against the extremist group, tweeting, "We must not allow ISIS to return, or enter, our country after defeating them in the Middle East and elsewhere. Enough!"

Records show Saipov was a commercial truck driver who formed a pair of businesses in Ohio after moving to the U.S. The first business, Sayf Motors Inc., used the address of a family friend near Cincinnati with whom Saipov had stayed for a couple of weeks after his arrival in the country. The second, Bright Auto LLC, used an address near Cleveland.

'He always used to work'

A trucking industry website listed Saipov at a Paterson, N.J., address that authorities were searching Tuesday night. Court records related to trucking-related infractions list Saipov with addresses in Paterson and the Cleveland suburbs.

The family friend with whom Saipov stayed in Ohio, Dilnoza Abdusamatova, told The Cincinnati Enquirer Saipov was "really calm" and worked hard.

This Snapchat video appears to show a suspect fleeing after a truck slammed into people on a NYC bike path 0:43

"He always used to work," Abdusamatova said. "He wouldn't go to parties or anything. He only used to come home and rest and leave and go back to work."

Police said Saipov rented the truck at about 2 p.m. ET in New Jersey, entering the bike path about an hour later on West Street a few blocks from the new World Trade Center, the site of the deadliest terror attack in U.S. history. The truck then turned at Chambers Street, hitting the school bus and injuring two adults and two children.

Handwritten note

A paintball gun and a pellet gun were found at the scene, police said. At least two covered-over bodies could be seen lying on the bike path, and the front end of the truck was smashed in, as was the side of the school bus.

Two law enforcement officials said a note was recovered inside the truck. One official said the note was handwritten in a foreign language, possibly Arabic.

Police investigators check out the truck used to run people over. (Andrew Kelly/Reuters)

The contents were being investigated, but the officials said the document supported the belief the act was terrorism. The officials were not authorized to speak publicly about an ongoing investigation and spoke to The Associated Press on the condition of anonymity.

Tom Gay, a school photographer, heard people saying there was an accident and went down to West Street, where a woman came around the corner shouting, "He has a gun! He has a gun!"

5 dead from Argentina

Gay said he stuck his head around the corner and saw a slender man in a blue track suit running on West Street holding a gun. He said a heavyset man was chasing him.

He said he heard five or six shots, and the man in the tracksuit fell to the ground, gun still raised in the air. He said a man came over and kicked the gun out of his hand.

Bicycles and debris can be seen on a bike path after people were run down. (Craig Ruttle/Associated Press)

Argentina's foreign ministry said five of the dead hailed from that country. Belgian officials said one of the dead was from there.

Prime Minister Justin Trudeau said he was "deeply grieved" by the attack and offered condolences on behalf of all Canadians to those mourning the loss of family members and friends. He also offered wishes for a full recovery to those who were injured.

NDP Leader Jagmeet Singh took to Twitter, tweeting "Sending my love, thoughts and prayers to all those impacted by the tragic violence in Manhattan today, along with all first responders."

The city's Halloween parade went on as scheduled after the attack, but security was increased, with extra officers, heavy-weapons teams and sand trucks parked as protective barriers along the route.

A Home Depot Inc. spokeperson said the company, based in Atlanta, was "fully co-operating" with law enforcement in the truck attack investigation.