Unprecedented security precautions expected in Times Square on New Year's Eve

— -- More than a million people are expected to ring in the new year in New York City's Times Square, making the crowded tourist site an inherent target, experts say.

The security precautions that will be taken by the New York Police Department to protect the revelers are expected to be unprecedented. Typical security measures, like using sand trucks and blocker vehicles on nearby cross streets and a mix of plainclothes and uniformed officers, will be deployed as always, but other steps, such as increasing security at nearby parking garages and closer surveillance of large rental trucks, are also being put in place, city officials said, according to local ABC station WABC.

Police officials are expected to make more detailed disclosures about their plans on Thursday.

John Cohen, a former counterterrorism coordinator for the Department of Homeland Security and current ABC News contributor, said that it is "not surprising at all" that security is being increased this year "based on how the threat facing the country has evolved."

"It's very possible that our traditional intelligence techniques for detecting threats are not well suited to uncover potential attacks," Cohen said, adding that it means that more precautions are necessary.

"In the current threat environment, the public plays a major role in both helping to detect potential attacks and being prepared in the event they find themselves at a location where an attack is unfolding," Cohen said.

Matt Olsen, a former director at the National Counterterrorism Center and current ABC News contributor, told "Good Morning America" that increased security is a must.

"People should expect to see an increase in security this New Year's because of an ongoing threat we've seen from ISIS. Really over the past few years, they've sought to encourage their followers to carry out low-level attacks wherever they can, particularly targeting people where they gather in crowds," Olsen said.

A joint assessment report for New York's New Year's celebration was released on Dec. 21 culling the findings from multiple agencies, and it concluded that there was "no information to indicate a specific, credible threat" toward the Times Square celebration, but officials and the public should be cautious nonetheless.

The report stated that the FBI, DHS, NYSP, PAPD, NYPD and FDNY "remain concerned about international terrorists and domestic extremists potentially targeting the event."

Specific attacks were cited, like the recent attacks in New York City, which include a car-ramming in October and an attempted attack at Port Authority earlier this month, and older attacks like the 2013 Boston Marathon bombing.

The report went on to list three specific instances in which Times Square was an intended target. One example was a summer 2016 plot described as more aspirational than operational in which three individuals planned to detonate improvised explosive devices at different targets in New York City -- including Times Square. The three individuals in question were arrested in the plot.

New York is not the only city that has law enforcement officials concerned about keeping celebrants safe. A similar threat assessment report was released by the Southern Nevada Counterterrorism Center and the Office of Intelligence and Analysis evaluating the potential threats facing partygoers in Las Vegas on New Year's.

The report states that since many of the festive events in Sin City "are being held on congested sidewalks and in high-rise buildings, presenting logistical challenges that make it difficult to secure the event from overhead threats." In October, 58 people were killed in Vegas when a man opened fire on a crowd of concertgoers from the 32nd floor of a hotel.

The report specifically cited that shooting, adding that "the risk of copycat attacks by terrorists and unaffiliated lone offenders is of particular concern to the SNCTC, as it highlighted a vulnerability associated with large crowds in open spaces."