NEW YORK - The setting could pass for a high-tech trading floor: men in dark suits, sitting at tiered banks of desks, studying a steady stream of video and data on floor-to-ceiling monitors.

But the front doors to the 28th-floor office near Wall Street are unmarked, and the men aren't fixated on market fluctuations. The stakes in their line of business, they say, are much higher.

The tenants - counterterrorism officers with the New York Police Department - have transformed the space into the new nerve center for a plan to protect Lower Manhattan from terrorist threats.

The center quietly began operating earlier this month, the first phase of a $100 million project sparked by the Sept. 11, 2001, attack that destroyed the World Trade Center.

The project will rely largely on 3,000 closed-circuit cameras covering roughly 1.7 square miles in and around the financial district. So far, about 150 cameras are in place, with 250 more expected to come on line by the end of the year and the rest by 2011.

The program was modeled in part after the "ring of steel" surveillance measures in London's financial district.

"I believe we'll have the safest business district in the world," Police Commissioner Raymond Kelly said during a recent visit to the command center, in an office tower that also houses brokerage, research and insurance firms.

A reporter was allowed into the nerve center on the condition he not disclose its exact location.

The 33 officers assigned to the center monitor the live feeds round-the-clock. As the volume of images increases, the NYPD hopes to incorporate "smart surveillance" software that can detect possible signs of trouble - an unattended bag, an unauthorized vehicle - and sound an alarm.

On the street, 30 police cars with two roof-mounted cameras have begun reading license plates of passing and parked cars; 96 stationary readers also will be installed. Computers check the scanned plate numbers against a database of stolen and suspicious cars, while interactive maps help officers pinpoint their locations and track their movements.

The command center eventually will also receive data from devices designed to detect any radiological and biological threats posed by vehicles crossing through the neighborhood on Canal Street or entering the 16 bridges and four tunnels serving Manhattan. About a million vehicles drive onto the island every day.