After the Paris attacks in November, ISIS terrorists released a propaganda video showing images of Times Square and a suicide bomber.

New York City's police commissioner admits New York remains the world's top terrorist target, but he says there's no credible threat against the New Year's Eve celebrations.

Nevertheless, the mayor says this year's security measures are "more extensive than ever."

On December 31st, every single person entering Times Square will be screened. There will be roughly 6,000 police officers on hand in this area and also will be a new counter-terrorism unit that consists of more than 500 heavily-armed and specially-trained officers.

New Year's Eve Ball The Times Square New Year's Eve Ball is tested atop the roof of One Times Square on the day before New Year's Eve celebrations in the Manhattan borough of New York December 30, 2015. Photo: REUTERS/Lucas Jackson

The police department has increased the number of mobile cameras, helicopters and police boats. Officers will be patrolling from rooftops and dogs will be sniffing for bombs. They have been empowered to shut down the event at any time and evacuate the area if necessary.

"New York City has now secured the Macy's Day Parade, the marathon and other large-scale events without any incident. New York City is the best prepared city in this world for handling an event like this," said Thomas Ruskin, president of CMP Group Security.

The New York Police Department (NYPD) said it is "very, very confident that New Year's Eve inNew York City will be the safest place in the world to be."

The NYPD launched a unique program in 2003 that places counter-terrorism intelligence officers in 11 international cities to provide information directly to the police department.

Ruskin, a former New York detective, says lessons are always learned from attacks abroad.

"Every event around this world changes things and when you have people - innocent people - killed in a terrorist attack, every single government, every single law enforcement agency studies that to make sure that you take every precaution to make sure that doesn't happen in your jurisdiction," said Thomas Ruskin.

The extra security will increase the wait time for the million or so expected participants, but officials are quick to caution those celebrating: if you see something, say something.