The Secret Service has now been empowered to use intrusive cellphone-tracking technology, also known as "stingrays," without a warrant if a nonspecific threat to the president or another protected person is ascertained.

While civil libertarians and privacy advocates have long been skeptical about the device, which mimics cell-towers in order to locate phones and identify their owners, the devices don't listen in to phone calls or capture text messages, said Homeland Security Assistant Secretary Seth M. Stodder while describing the department's policy on the use of cell-site simulators to a House subcommittee, the Associated Press reported.

A similar policy was announced by the Justice Department and FBI in September.

Stodder said the policy would let the Secret Service use stingrays in "exceptional circumstances," wherein using the devices would require direct approval from "executive-level personnel" at Secret Service headquarters and the U.S. attorney for the relevant jurisdiction, according to AP.

"The key exception that we envision is the Secret Service's protective mission. In certain circumstances where you could have an immediate threat to the president and you have cryptic information, our conclusion in drawing the line between security and privacy here is to err on the side of protection," Stodder said.