NYPD Commissioner Ray Kelly told CBS in New York his department is looking to deploy Terahertz Imaging Detection scanners on the street in the war on “illegal guns.”

Kelly said the scanners would be used in “reasonably suspicious circumstances” and intended to cut down on the number of stop-and-frisks on the street. So called stop-and-frisks are considered a violation of the Fourth Amendment.

New York City is largely a Second Amendment free zone. The city’s mayor, Michael Bloomberg, has said that citizens “acting outside of any governmental military effort” should not be allowed to protect themselves with firearms.