Privacy groups are asking regulators to discipline phone companies that sell subscriber information to third parties, including the CIA.
The groups petitioned the Federal Communications Commission in response to a New York Times report that said AT&T had sold subscriber records to the intelligence agency.
Laura Moy, a staff attorney at Public Knowledge, urged the FCC to "vigorously" enforce the Communications Act's privacy protections.
"Americans should be able to rest assured that carriers can’t just turn around and secretly share or sell that information with marketers or the government without consent," Moy said in a statement.
Public Knowledge warned it has found that the four major mobile carriers — AT&T, Sprint, T-Mobile and Verizon — "all have privacy policies that indicate that it is okay to sell or share similar records."
“Consumers have no choice but to share vast quantities of personal and private information about themselves with phone carriers in order to obtain service, which is an absolute necessity in the modern age," Moy said.
In addition to Public Knowledge, the privacy groups signing the letter included the Electronic Frontier Foundation, the Electronic Privacy Information Center, Free Press and the New America Foundation’s Open Technology Institute.
— This story was updated at 1:49 p.m.