The war on terrorism in New York is run by Police Commissioner Ray Kelly out of the NYPD command and control center. Since the start of the war in Iraq, it has been staffed 24 hours a day by police detectives, FBI agents, state troopers and emergency management personnel who are monitoring what is going on in every precinct in the city.
They receive live pictures from 100 video cameras of some of New York's highest profile potential targets: landmarks, bridges, tunnels and the city's subway system.
It is all part of "Operation Atlas," a $5 million-a-week battle against terrorism in a city that has already been attacked twice and had its bridges and tunnels threatened twice.
We asked Commissioner Kelly how likely he thinks it is that New York will be targeted again. "Clearly, we've been targeted here four times. So we're on the terrorist target list, that's certain," he said. "We believe that we're doing a lot to prevent another terrorist attack. It's all about deterrence. It's all about deterrence."
The enormity of the task is striking. In addition to having the tourist attractions that everyone recognizes, New York City has hundreds of thousands, if not a million, commuters who come into the city every day. How do you monitor it all?
"It is a challenge, no question about it," says Kelly. "We have 500 miles of coastline. We have the UN here. We have the Statue of Liberty. We have the Brooklyn Bridge. We have the New York Stock Exchange. So it's challenging. But we have an awful lot of things in place to protect the city and prevent another attack."
What are the city's vulnerabilities? "I don't think we should be too specific in that area," Kelly replies. "But clearly an attack by weapons of mass destruction, nuclear, biological, chemical instrumentalities, would cause us great concern."
In response to that threat, the police department recently began randomly stopping vehicles and testing them for radioactive material. This week, the NYPD began distributing some 15,000 chemical and biological weapons kits, including gas masks and respirators, to its officers.
The New York City Police Department has transformed itself since the September 11 attacks. Now, 4,000 officers are assigned to fight terrorism. That's more than 200 times what it had just a year ago.
While the commissioner concedes there are no guarantees, his police force is trying to protect the city from all directions. By air, with six helicopters flying every day, watching for signs of suspicious activity. By sea, the department's harbor patrol has deployed 24 boats in response to recent intelligence reports that terrorists connected to Al Qaeda could be plotting an attack from the waters surrounding New York City.
What kind of attack could come from water? "I could think of lots of ways that you would attack a target from the water," Kelly replies. "I mean, any way that you can deliver explosives to a sensitive location." That means buildings, ships, bridges, tunnels, ferries.
The city's most visible and dramatic counter-terrorism measure is on land. A group of highly trained and heavily armed police officers known as Hercules teams are being dispatched day and night throughout the city in unpredictable patterns.
Their aim is to display an intimidating and very public show of force. Police Commissioner Kelly says his department has learned that this tactic may be an effective deterrent to terrorist groups like Al Qaeda.
"We have done a fairly comprehensive examination of Al Qaeda doctrine, Al Qaeda documents," says Kelly. "We know that they make a major commitment to reconnaissance. They make a major commitment to planning. We know that any change in the security pattern can be disruptive of their plans. So if you change the pattern of normal security or normal enforcement, we believe that can be disconcerting and disruptive."
In just one day, the Hercules teams were sent to more than two dozen locations, including the Staten Island Ferry, the New York Mercantile Exchange, and the Plaza Hotel, all determined by specific intelligence reports analyzed by the department's new head of intelligence.
David Cohen is a 35-year veteran of the CIA. "We're putting together a defensive shield against those areas that we think based on intelligence would be the highest target threats," he says.
Success is difficult to measure. "We've dealt with a broad range of suspicious activity. We don't know if imbedded in any one of them was a threat that has either been terminated, postponed, put on the shelf. And that's why the job is unrelenting and needs to be continued," Cohen says.
Perhaps the most important job in New York City's war on terrorism takes place at the top-secret high-tech headquarters of the NYPD' s counter-intelligence unit.
That is where some 125 detectives analyze satellite images of New York, looking for the slightest abnormalities, and share intelligence data with police departments around the world. Language specialists monitor foreign news broadcasts for terrorist threats.
The unit also investigates tips from the public about suspicious behavior. "We receive on average, I'd say, 30 to 40 calls a day. With the start of the war, we're probably up to about a 100 to 150 calls a day," says Captain Michael O'Neil, who runs the unit.
With a higher awareness of terrorists and terrorist behavior, more New Yorkers are looking for it out on the streets.
The counter-intelligence unit assumes that Americans are at greater risk since the war started, and that the number one target is New York City.
"I don't think there's any question about that," says David Cohen. "I think the experts in the field who worry about terrorism day in and day out at all levels would say that New York would be their number one target if they could get here. And the consequences of them getting here are enormous. Another terrorist event in the city of New York would have a tsunami effect across the country in terms of its economic, political and societal consequences. You couldn't contain the impact of another terrorist event in New York."
Cohen admits he doesn't sleep very well at night these days.
But New York Mayor Michael Bloomberg says that New Yorkers should go on with their lives even though the city is a target and on high alert.
"Don't let the terrorists win without firing a shot," he says. "Go out."
His weekend plans included a Knicks game, dinner out, a couple of Oscar parties, and visits to several churches on Sunday morning.
But with a budget deficit this year of $3 billion, New York City cannot fight its war on terrorism without help. Bloomberg has asked the White House for as much as $900 millions. So far, the city has received only a fraction of that request.