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.