The New York City Police Department is testing a new counter-terror technology to help law enforcement prevent a "dirty bomb" attack.
Officials say 2,000 officers will carry radiation detectors around the city, sending real-time alerts to a Manhattan command center.
An NYPD official says the detectors should be deployed in a few months.
The program is part of the "ring of steel," a Lower Manhattan security initiative.
It's being tested under the watch of federal authorities, in the hopes it can later be used elsewhere.
Intelligence officials have said terrorists want to launch radiation attacks on American cities.