President Donald Trump has responded to the terror attack in New York City, saying that the attack appears to have come from a "sick and deranged" person.

"In NYC, looks like another attack by a very sick and deranged person," Mr Trump tweeted. "Law enforcement is following this closely. NOT IN THE USA!"

The President was joined by his wife in condemning the attacks and expressing grief for the victims of the attack.

"My heart breaks for #NYC today," Melania Trump wrote on Twitter. "Thoughts & prayers as we monitor the situation."

At least eight people were killed after the truck smashed through the bike lane, and at least a dozen more were injured, according to New York City Mayor Bill DeBlasio, who addressed reporters during a press conference following the violence.

"It is a very painful day in our city," Mr DeBlasio said. "Horrible tragedy on the west side."

New York Truck attack Show all 6 1 /6 New York Truck attack New York Truck attack Investigators inspect the truck following the attack Investigators inspect a truck following a shooting incident in New York on 31 October 2017. Several people were killed and numerous others injured in New York on Tuesday when a suspect plowed a vehicle into a bike and pedestrian path in Lower Manhattan, and struck another vehicle on Halloween, police said. A suspect exited the vehicle holding up fake guns, before being shot by police and taken into custody, officers said. The motive was not immediately apparent. Getty New York Truck attack A paramedic looks at a body along the bike path A paramedic looks at a body covered under a white sheet along the bike path 31 October 2017, in New York. A motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people Tuesday, police and witnesses said. AP Photo/Bebeto Matthews New York Truck attack The truck driver collided with a school bus Authorities respond near a damaged school bus Tuesday, 31 October 2017, in New York. A motorist drove onto a busy bicycle path near the World Trade Center memorial and struck several people, police and witnesses said. Two adults and two children were on the bus at the time. AP Photo/Bebeto Matthews New York Truck attack A young girl reacts to the scene A young girl reacts as police officers secure an area following a shooting incident in New York on 31 October 2017. Several people were killed and numerous others injured in New York on Tuesday after a vehicle plowed into a pedestrian and bike path in Lower Manhattan, police said. 'The vehicle struck multiple people on the path,' police tweeted. 'The vehicle continued south striking another vehicle. The suspect exited the vehicle displaying imitation firearms & was shot by NYPD.' DON EMMERT/AFP/Getty Images New York Truck attack Police officers arrive at the scene Police officers arrive at the scene following a shooting incident in New York on 31 October 2017. Multiple people were hurt in downtown Manhattan, US media reported after police confirmed that they were responding to reports of a shooting. Police said they had mobilized to the scene in Lower Manhattan and that one person was in custody, giving no further details. DON EMMERT/AFP/Getty Images New York Truck attack Emergency personnel respond to truck attack in lower Manhattan Emergency personal respond after reports of multiple people hit by a truck after it plowed through a bike path in lower Manhattan on 31 October 2017 in New York City. According to reports up to six people may have been killed. Kena Betancur/Getty Images

Mr DeBlasio and law enforcement officials said that they were treating the incident as a terrorist attack, and said that the suspect was detained by a police officer on duty after the truck smashed into a school bus near Chambers Street. They did not immediately release the name of the suspect.

The suspect, 29-year-old Sayfullo Saipov from Uzbekistan, was shot and arrested by police after exiting the truck armed with a pellet gun and a paintball gun.

Images from the scene showed bikes mangled and strewn along the path in the area where the truck hit between Houston and Chambers street.