NEW YORK, Oct. 31 -- New York City stepped up security for the annual Halloween parade on Wednesday, a year after the holiday was scarred by a terror truck attack which claimed eight lives and injured a dozen in lower Manhattan.

New York Police Department Commissioner (NYPD) James O'Neill said on Tuesday that the police would use blocker vehicles to make sure there's no "unauthorized vehicles" on the route of the parade, with thousands of officers in both uniforms and plainclothes to be in place for the normally crowded event.

The police will try to ensure that the holiday is celebrated in an atmosphere of community, peace and fun, and "certainly not fear," said O'Neill.

Though no credible threats are known yet, there remains "a level of concern," said NYPD Chief of Patrol Rodney Harrison. "So we're going to continue to ask people to be vigilant."

On Oct. 31 last year, 30-year-old Sayfullo Saipov plowed a rented truck onto a popular downtown bike lane beside the Hudson river, in the deadliest terror attack that struck New York city since 9/11. Saipov was later identified as a sympathizer of the Islamic State terrorist group.

The attack occurred just hours before the traditional Halloween parade in the city, which was held as scheduled amid tight security.

At a memorial service held on Wednesday morning at the site of the 2017 attack, New York Mayor Bill de Blasio remembered the victims of the incident along with their family members and friends.

"For the families, (this) is a pain that will never go away," he said.

Newly-added concrete barriers and steel posts can be seen alongside the bike path, and more will be installed in the coming months across the city, as the NYPD has promised.

Also, a new bill was slated to be introduced in the New York City Council on Wednesday to demand ID verification for truck rentals.

Donovan Richards, a City Councilman with the borough of Queens, proposed the bill as a way to better safeguard against terror attackers using vehicles.