U.S. cell carriers have responded to more than 1.3 million demands for customer data by the U.S. law enforcement agencies in the past year.
Nine carriers, including Verizon, AT&T, Sprint, and T-Mobile, responded to the Congressional inquiry, which showed a massive uptick in requests for subscriber data over the past five years, according to The New York Times.
The inquiry emerged as U.S. cell carriers oppose California's location privacy law, in which police would be forced to obtain a search warrant in order to track a subscriber's location. Only in emergency cases would a warrant not be required, but a judge would have to approve.
In a rare move, law enforcement and government agencies, and cell networks are reading from the same page as they join in opposition.
Most of the data sought by law enforcement relate to the content of text messages and caller location details.
In many cases, law enforcement and government agencies requested thousands of records per day --- with most responding to emergency requests, though many were 'slower' requests relating to subpoenas and court orders.
The data was not broken down by government agency or law enforcement unit, but it was noted that all levels of government sought access to subscriber data throughout the recorded period.
Such data includes GPS tracking that allows police to track suspects or those on the run, including finding victims of crime. Sprint and others have asked for legal clarity in turning over location data, however.
AT&T, the second largest U.S. network, with more than responds to around 700 requests per day, with around a third that were considered emergencies and do not require a court order or subpoena.
Sprint, said it responds to around 1,500 requests per day, marking the most requests out of all the carriers.
Meanwhile, T-Mobile said it had passed on two law enforcement requests for data to the FBI after the cell giant deemed the demands "inappropriate," though no further details were given.
Also, because law enforcement can request a "cell tower dump" for suspects that were near the vicinity of a cell tower, this can lead to tens if not hundreds of thousands of subscriber names depending on the nearby population density.
However, while cell snooping increases, wiretapping warrants allowing law enforcement to listen in on others' calls dropped by 14 percent, the Times reported.