After the Department of Homeland Security (DHS) recently admitted that it has detected signs of "nefarious actors" using Stingrays—which operate as fake cellphone towers—to intercept the communications of U.S. officials and ordinary Americans in the nation's capital, Sen. Ron Wyden (D-Ore.) on Tuesday accused FCC chair Ajit Pai of "stonewalling" a probe into the potential spying activity and demanded that the agency launch an investigation immediately.

"Mr. Pai and the FCC are dragging their feet here," Wyden told The Hill in an interview on Tuesday. "They are ducking. They are trying to conjure up any possible reason to sit it out."

Wyden went on to argue that the telecom industry "bears some of the blame" for the new surveillance concerns and "pressed it to take steps to guard Americans from potential spying," The Hill reported.

While Wyden has been consistent in highlighting the possibility that such government technology could be used to invade Americans' privacy, DHS's Stingray report has sparked unusually broad concern on Capitol Hill, given the possibility that lawmakers who are usually supporters of mass surveillance could now be the victims of spying.

Ostensibly intended as a tool for law enforcement agencies to track "criminal suspects," civil liberties groups have repeatedly accused police departments of using Stingrays to violate Americans' privacy and surveil peaceful demonstrators.

As of March of this year, ACLU estimates that 73 agencies in 25 states and D.C. own Stingrays, but the actual number is difficult to determine because use of the technology remains shrouded in secrecy.

"This is not a new problem," Drew Mitnick, policy counsel at the digital rights advocacy group Access Now, told The Hill in response to the DHS's findings. "We see catchers used pretty broadly by state, local, and federal law enforcement. There hasn't yet been success in establishing the appropriate limits on the use of these devices."

Wyden is hardly the only lawmaker raising concerns about the possible use of Stingrays in Washington, D.C. and the federal government's refusal to investigate the matter, which has privacy implications for millions of Americans.

Following DHS's admission that it has found signs of Stingray use on Capitol Hill, Reps. Frank Pallone Jr. (D-N.J.), Eliot Engel (D-N.Y.), and Bennie Thompson (D-Miss.) sent a letter urging the FCC to immediately investigate what they described as an "incredible security vulnerability."

"With foreign actors now potentially taking advantage of the commission's inaction, the FCC should act, consistent with applicable law and regulations, to investigate these allegations and address any unlawful use of cell-site simulators in the capital and anywhere else they are used on U.S. soil," the congressmen wrote.