NEW YORK (CBSNewYork) — A week-long series of terror drills involving dozens of agencies and first responders begins Tuesday in the Big Apple. The focus will be on one of the great concerns of the post-9/11 era: nuclear terrorism, Jay Dow reports.

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The NYPD and 70 other law enforcement agencies across our region will test their ability to detect radiological materials and prevent an attack orchestrated by four fictional terror cells intent on targeting New York City with a “dirty bomb.”

The drill began with a massive deployment Tuesday morning at the United Nations, and will run through Saturday.

NYPD Commissioner Ray Kelly said New Yorkers can expect to see a heightened presence near bridges, transit hubs, and on the waters around New York City.

“We’ll be manning up to 400 checkpoints throughout the Metropolitan Area to test our ability to intercept radiological material. There actually will be samples of radiological materials,” he said.

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Kelly said over the next five days, residents can expect to see a heightened presence near bridges, transit hubs, and on the waters around New York City.

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“The goal is to exercise our capacity to intersect radiological material coming into the city,” he said.

The exercise will be supervised by an outside consultant and, with overtime pay inevitable, funded by a federal grant.

“We’ve distributed, both in the New York City Police Department and other agencies throughout the Metropolitan Area 4,200 radiation-detection devices,” said Kelly

Particular areas that will be impacted include the Macombs Dam Bridge, the 225th Street Bridge, the 138th Street Bridge, the 155th Street Bridge and the Third Avenue Bridge.

“We need to be protected by whatever means necessary,” said Pierre Baptiste of Manhattan.

“With what’s happening in the world, it’s needed. We’re at war on all fronts, so it’s best to start here. Sooner or later it’s going to get here,” said Charles Watson of the Bronx.

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Is New York prepared for a terror attack? Is enough being done to secure nuclear material worldwide? Sound off in our comments section.