New York (AFP) - Measures to protect the hundreds of thousands of revelers who will ring in 2016 in New York are "more extensive than ever," Mayor Bill de Blasio said Tuesday, amid global fears of an attack during New Year's Eve celebrations.

The Big Apple is a popular destination on December 31, with about one million people packing into Times Square every year for the countdown to midnight and the traditional ball drop.

"I certainly understand that everyone's concerned and I want everyone to understand and to hear that the NYPD is ready," De Blasio said in a local radio interview.

"The planning is extraordinary. We'll have a huge number of police out on New Year's Eve, including a lot of our new anti-terror force, the Critical Response Command. That's 500-plus officers ... who are specialized in preventing terror."

A total of about 6,000 officers will be on hand, the city's police chief Bill Bratton told reporters, noting that some would be in plain clothes.

After the Paris attacks on November 13, an Islamic State group propaganda video broadcast images of New York from Times Square.

Authorities have since sought to reassure a jittery public that the Big Apple is safe.

"This is the best prepared city in this country to stop terrorism, and people should rest assured that they will be very well protected on New Year's Eve," De Blasio said.

Bratton said authorities were "not aware of any threat that we deem credible to New Year's Eve celebrations in NYC."