As the president of the United States visits his home town and biggest city in America – the largest police force in the country awaits him.

Among the 36,000 men and women in the New York Police Department, there is a team of 1,500 devoted to one job: Counterterrorism.

And with the president in town, their job becomes that much more critical.

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John Miller, NYPD deputy commissioner of intelligence and counterterrorism, told Fox News the task is challenging.

"We are protecting the president of the United States, if he is in residence, working for the Secret Service,” Miller said. “Two, if he is not in residence, we are protecting a building that went from one of the buildings on Fifth Avenue to what could be argued is now a symbolic target."

It’s a job that takes intense training and many layers within the NYPD.

Layer one: Officers armed with long guns visible to the public guarding Trump Tower. Together, with the Secret Service, the Counterterrorism Critical Response Command teams, otherwise known as the CRC, have President Trump's every step covered.

Layer two: The not so visible NYPD counter-sniper team. Fox News got an exclusive, behind-the-scenes look at how they train.

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NYPD Sgt. Kevin Whelan said the team of 30 men and women "use a magnified scope at 200 yards that allows us to center in our target and crosshair our target at 200 yards, just as if it was 25 feet away."

Layer three: An eye in the sky.

The NYPD’s Emergency Service Unit, also known as the ESU, not only has a plan A, B, and C in place –- but if things get bad there's a plan D. Teams are at the ready to respond to the unpredictable. Officers can deploy from a helicopter and rappel onto any platform anywhere in the city within minutes.

It’s a tremendous resource in terms of people and costs.

New York City has spent tens of millions of dollars protecting Trump and New York City since he announced his candidacy. Officials estimate it costs just under $150,000 a day to protect Trump Tower alone. That daily cost doubles to about $300,000 when the president is in town.

But there is good news for New York City taxpayers, Congress announced this week it has approved a federal budget deal that will reimburse the city and will foot the massive security bills moving forward.