One person is in custody after driving down a bike path in lower Manhattan on Tuesday afternoon and killing multiple people in what police are calling an act of terrorism, according to the New York City Police Department.

At least eight people were killed and 12 injured, according to police. Six were confirmed dead on the scene, and two were pronounced dead at the hospital.

New York City Mayor Bill de Blasio confirmed the incident was an act of terror.

"We know this action was intended to break our spirit, but we also know New Yorkers, New Yorkers are resilient and our spirit will never be moved by an act of violence and an act meant to intimidate us," de Blasio said during a press conference.

The suspect, 29, is in custody, according to police. Multiple outlets have identified the suspect is Sayfullo Saipov of Tampa, Fla., but police declined to release the attacker's identify.

Police confirmed a truck drove in a bike lane off the West Side Highway at around 3:05 p.m., hitting multiple people. The truck collided with a school bus at Chambers St. and injured two adults and two children on board.

An officer on post near the scene of the attack stepped in and stopped "the carnage moments after it began," New York City Police Commissioner James O'Neill said.

New York police shot the driver of the car in the stomach after he exited the vehicle with two handguns, O'Neill said. Police recovered a paintball gun and pellet gun from the scene.

Multiple reports indicate the driver shouted "Allahu akbar" as the truck drove through the crowd. That phrase is Arabic for "God is great."

White House press secretary Sarah Sanders said White House chief of staff John Kelly briefed Trump on the incident in lower Manhattan and will be updated continually.

Trump responded to the incident on Twitter, saying the incident was perpetrated by a "very sick and deranged person."

"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.!" the president tweeted.

An investigation is ongoing, and agents with the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives are on the scene assisting the New York City Police Department.

There is no active threat, according to city officials.