WASHINGTON (AP) -- A new report finds that law enforcement agencies in the U.S. made more than 1.3 million requests for customers' cellphone records last year.

It's an alarming surge over previous years, reflecting the increasingly gray area between privacy and technology.

Sprint says it received about 500,000 subpoenas in 2011. Requests are increasing annually at Verizon and T-Mobile. And AT&T has a dedicated team of more than 100 workers whose job it is to handle police requests.

Cellphone carriers say they usually require warrants to hand over information, but not in emergencies, such as when there's an immediate threat to someone's life.

The information was collected by Massachusetts Rep. Ed Markey. He said laws need to be updated to ill protect people's Fourth Amendment rights against unreasonable searches using modern technology.