At least eight people are dead and many more are injured after a suspected terrorist drove down a busy bicycle path near New York’s World Trade Center memorial.

One man is in custody after a rented pickup truck ploughed into people in lower Manhattan on Wednesday morning (AEST).

The vehicle drove for a reported 20 blocks down the bicycle path before crashing into a school bus, injuring two children.

Witnesses reported the man shouted, “Allahu Akbar” (God is greatest) before being arrested at the scene.

• New York terror attack: What we know so far

New York Mayor Bill de Blasio confirmed the attack was an act of terrorism.

“It is a painful day in our city. A horrible tragedy on the West Side,” Mr de Blasio told a media conference. 

“Let me be clear, based on the information we have at this moment, this was an act of terror and a particularly cowardly act of terror aimed at innocent civilians,” he said. 

The attacker has been Uzbek-born Sayfullo Saipov. Photo: Twitter

New York governor Andrew Cuomo called it a “lone wolf” attack, and authorities have said there is no ongoing threat or evidence of a wider plot.

US media later quoted unnamed law enforcement officials as identifying the driver as Uzbek-born, 29-year-old, who lived in Tampa, Florida after arriving in the US in 2010.

He is reportedly in a grave condition in hospital.

New York Police Commissioner James O’Neill earlier said the driver was shot in the stomach by police after jumping out of the vehicle “brandishing” two weapons.

Commissioner O’Neill said the truck entered the west side highway bike path and began driving southbound striking pedestrians and cyclists along the route.

“At Chambers Street the truck collided with a school bus injuring two adults and two children,” he said.

The Commissioner said a paint ball gun and pellet gun were recovered at the scene. 

The gunman flees the scene

https://www.youtube.com/watch?time_continue=8&v=sQcaDZ_5hDc

Commissioner O’Neill earlier refused to confirm media reports on the driver or his condition pending further investigation.

A video posted on social media showed two people lying motionless on a bicycle path near Chambers and West Streets by Stuyvesant High School, after being struck by a white pick-up truck.

Home Depot confirmed to US media the vehicle involved was one of its rental trucks.

“We’re cooperating with authorities in their investigation,” the hardware retailer said in a statement.

Path of destruction

Mr de Blasio warned all New Yorkers to remain vigilant given the upcoming Halloween celebrations, due to start hours after the incident.

“We know it’s Halloween night and we know in the days ahead people will be uneasy. We ask all New Yorkers to live by the idea of ‘you see something, you say something’,” he said.

“Tell an officer immediately if you see anything unusual, anything that worries you, be vigilant and know that there will be extensive additional employments of NYPD officers this evening and throughout the days ahead.” 

New York City's leaders and residents vowed that the city would not be intimidated by acts of violence. Read more: https://t.co/8QjzPr5Qe9 pic.twitter.com/o5nYPWYFnl

— NBC News (@NBCNews) October 31, 2017

New York Fire Commissioner Daniel Nigro said six of the people killed – all male – were pronounced at the scene.

“Two others were transported in traumatic arrest and were pronounced dead at the hospital,” he said.

“We also transported 11 people, all with serious, but at this moment, not life-threatening injuries.”

Warning graphic images:

https://twitter.com/TRobinsonNewEra/status/925456635988004865

White House spokeswoman Sarah Huckabee Sanders said President Donald Trump has been briefed by White House chief of staff John Kelly and “will be continually updated as more details are known”.

“Our thoughts and prayers are with all those affected,” she said.

Mr Trump later tweeted his thoughts.

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.!

— Donald J. Trump (@realDonaldTrump) October 31, 2017

We must not allow ISIS to return, or enter, our country after defeating them in the Middle East and elsewhere. Enough!

— Donald J. Trump (@realDonaldTrump) October 31, 2017

Witness Ramon Cruz told CNN several mangled bicycles littered the popular footpath as people screamed that the suspect was carrying a gun.

“What I saw was that the driver – he didn’t look like he was bleeding,” Mr Cruz said.

“He was dragging his foot. He looks frustrated, panicked, confused. People are running past me, saying, ‘He’s got a gun. He’s got a gun.’ I didn’t see any gun.”

Uber driver Chen Yi told AP he saw the truck plow into people on the bicycle path, then heard seven or eight gun shots before police arrested the man.

“I saw a lot of blood over there. A lot of people on the ground,” Mr Yi said.

Authorities investigate the scene around a body covered under a white sheet. Photo: AP

No Australian victims

Acting Prime Minister Julie Bishop said the US State Department  had confirmed it did not believe any Australians were affected by the attack.

But the situation is still unfolding,” she warned while speaking on ABC radio.

Australia’s Consul-General to New York Alastair Walton was in the area along the Hudson River when the attack happened.

“He said there are children everywhere in New York today because of course it’s Halloween and it’s an enormous celebration,” Ms Bishop said.

“We think of those who have been affected by this, particularly those who have been killed, their family and friends must be devastated.”

Ms Bishop advised any Australians in New York to follow the direction of local authorities.