Updated

The New York Police Department is testing ground-breaking counterterror technology expected to dramatically increase its ability to detect and thwart a potential radiation attack, officials said Thursday.

The technology will allow a command center in lower Manhattan to monitor 2,000 mobile radiation detectors carried by officers each day around the city. The detectors will send a wireless, real-time alert if there's a reading signaling a dirty bomb threat.

The system already is being tested under the watch of federal authorities in hopes it can be perfected and used elsewhere.

"This is the first and only place you'll see it," said Jessica Tisch, an NYPD counterterrorism official. "It's been tested in the field. It works, and we're hoping to get (the wireless detectors) deployed in a few months."

A dirty bomb — intended to spread panic by using a small explosive to create a radioactive cloud in urban settings — has never been discovered or detonated in a U.S. terror plot. But law enforcement considers dirty bombs a serious threat because they're easy to build and because of intelligence that foreign terrorists want to use them against American cities.

The radiation detection system is being developed as part of a $200 million lower Manhattan security initiative. Police say the overall plan was inspired by the so-called "ring of steel" encircling the business district in London but is broader in scope and sophistication.

The initiative will rely largely on 3,000 closed-circuit security cameras carpeting the roughly 1.7 square miles south of Canal Street, the subway system and parts of midtown Manhattan. So far, about 1,800 cameras are up and running, with the rest expected to come on line by the end of the year.

In 2008, police began monitoring live feeds from the cameras round-the-clock at a high-tech command center in lower Manhattan, home to Wall Street, the new development at ground zero, and other sites needing heightened protection.

"We're talking about some of the most significant targets anywhere in the world," Police Commissioner Raymond Kelly said Thursday.

The NYPD is using a single, high-bandwidth fiber optic network to connect all its cameras to a central computer system. It's also pioneering "video analytic" computer software designed to detect threats, like unattended bags, and retrieve stored images based on descriptions of terror or other criminal suspects.