Wireless carriers say they received 1.3 million requests last year from law enforcement agencies for subscriber text messages, caller locations, and other information, reflecting a steady increase during the past five years.

Carriers' responses to a congressional inquiry, as reported by the New York Times, reveal that thousands of records were turned over on a daily basis in response to law enforcement emergencies, subpoenas, and other court orders.

Nine carriers supplied reports in response to the inquiry, including AT&T, Sprint, T-Mobile, and Verizon. The number of requests addressed by the study -- the first time law enforcement's cell surveillance has been studied at a national level -- surprised some officials who follow the issue closely.

"I never expected it to be this massive," Rep. Edward J. Markey, a Massachusetts Democrat who is co-chairman of the Bipartisan Congressional Privacy Caucus, told the Times. "There's a real danger we've already crossed the line."

Law enforcement requests for information have risen 12 percent to 16 percent for each of the past five years, the Times noted. AT&T said it now responds to more than 700 request a day, about a third of which do not require court orders or subpoenas, while Sprint said it logged the most requests for information than any carrier last year, reporting a daily average of 1,500 data requests.

In order to address all the requests and determine their legality, most carriers reported employing round-the-clock teams of lawyers and technicians, The Times reported.

The inquiry results emerge as wireless carriers side with law-enforcement agencies in opposing a proposed California location privacy law that would require police to obtain search warrants to track a wireless customer's whereabouts. Except in certain emergency situations, requests for location tracking would require a judge's approval.

Federal legislation introduced last year would require police to obtain a warrant signed by a judge before monitoring someone's movements, and courts have split over whether warrantless tracking is constitutional. In May, Sen. Al Franken (D-Minn.) asked the Justice Department to hand over any information it might have about law enforcement agencies getting their hands on location data from cell phone companies.

The explosion in official requests for information mirrors an increase in government activity on the Internet. In June, Google reported an "alarming" incidence in government requests to censor Internet content in the past six months. The Web giant said in its biannual Global Transparency Report that had it received more than 1,000 requests from governments around the world to remove items such as YouTube videos and search listings.