Police are spying on millions of Americans by getting cellphone records from mobile carriers.

Federal, state and local law enforcement agencies made upwards of 1.3 million requests for consumers' cellphone records last year, according to a report by Congressman Edward J. Markey.

The requests ask for an individual's texts, caller locations and other information as well as “cell tower dumps” in which carriers provide all phone numbers connected to a specific tower at a given time.

We have covered how the National Security Agency (NSA) intercepts 1.7 billion U.S. electronic communications every day, the Department of Homeland Security (DHS) is running a massive spying campaign on Occupy Wall Street and the FBI has formed a secretive surveillance unit to better enable police to eavesdrop on Americans' Internet and wireless communications.

But Markey's report is the first data collected nationally on the frequency of cell surveillance by law enforcement. The Democrat from Massachusetts asked nine mobile wireless carriers about their policies and practices for sharing their customers’ mobile phone information with law enforcement.

“Law enforcement agencies are looking for a needle, but what are they doing with the haystack?" Rep. Markey, who is co-Chair of the Congressional Bi-Partisan Privacy Caucus, said in a statement. "We need to know how law enforcement differentiates between records of innocent people, and those that are subjects of investigation, as well as how it handles, administers, and disposes of this information.”

The nation's two largest carriers, Verizon and AT&T, reported 260,000 requests last year while Sprint received about 500,000. AT&T responds to an average of more than 700 requests a day, including about 230 that don't require the normal court orders because authorities claim there is an imminent threat of death or serious injury.

Markey said tens of millions of Americans could be affected by the requests – as one request could net info of dozens or hundreds of people – and that the number is increasing every year.

The practice has disturbed privacy advocates since so many Americans carry cellphones with GPS and it's unclear whether the Fourth Amendment's guarantee against unreasonable searches applies to cellphone data.

David Kravets of Wired points out that "if police wanted to try to find a person who broke a store window at an Occupy protest, it could get the phone numbers and identifying data of all protestors with mobile phones in the vicinity at the time — and use that data for other purposes."

Eric Lichtblau of the New York Times reported that the "total number of law enforcement requests last year was almost certainly much higher than the 1.3 million the carriers reported to Markey."

In light of the report, the Electronic Frontier Foundation (EFF) said cell phone companies need to start releasing transparency reports and Congress needs to immediately pass legislation requiring a warrant for GPS location information.