Washington - US mobile carriers provided some one million records to law enforcement in 2012 related to warrants, wiretaps, location data and "cell-tower dumps", documents released by a US senator showed.
The documents do not detail information handed over to the National Security Agency, which is classified, but nonetheless raise concerns over privacy laws for mobile phones.
Senator Edward Markey (D-MA), who released letters from the carriers, said he would introduce legislation to curb the practice of so-called "bulk" collection of phone records on large numbers of innocent people.
"As law enforcement uses new technology to protect the public from harm, we also must protect the information of innocent Americans from misuse," Markey said in a statement.
"We need a Fourth Amendment for the 21st century," he said, referring to the constitutional guarantee against unreasonable searches and seizures.
"Disclosure of personal information from wireless devices raises significant legal and privacy concerns, particularly for innocent consumers. That is why I plan to introduce legislation so that Americans can have confidence that their information is protected and standards are in place for the retention and disposal of this sensitive data."
The data showed AT&T and T-Mobile each provided data in 297 000 instances and Verizon in more than 270 000.
Sprint said it had no aggregate count but that it provided real-time location data to law enforcement in 67 000 instances in 2012; it also provided emergency or public safety information in 53 000 cases, 22 000 "pen register trap and trace" requests and 17 400 wiretaps.
Smaller companies also provided data - Cricket/Leap Wireless in 59 000 instances and US Cellular in 20 000.
Christopher Calabrese, of the ACLU, said the lack of privacy protections for cell data raised concerns.
"Have no doubt, police see our mobile devices as the go-to source for information, likely in part because of the lack of privacy protections afforded by the law," said Calabrese in a statement.
"Our mobile devices quite literally store our most intimate thoughts as well as the details of our personal lives. The idea that police can obtain such a rich treasure trove of data about any one of us without appropriate judicial oversight should send shivers down our spines."
Among the requests are so-called cell-tower "dumps", to records from cell towers of all the phones connected, to allow law enforcement agencies to locate a subject.
Markey, a Democrat, said the carriers reported some 9 000 data "dumps" and that this could mean the records of many consumers might have been obtained with little or no legal justification.
"If the police want to know where you are, we should know why," said Markey.
"When law enforcement access location information, it as sensitive and personal as searching an individual's home and should be treated commensurately."
The carriers charge fees in many cases for these services to law enforcement.
AT&T said it collected $10m in 2012, and that it employs around 100 people full time to handle law enforcement requests.
T-Mobile said it was paid $11m while Verizon said it received less than $5m "complying with the many court orders or warrants we receive for wiretaps, pen registers, traps and traces and text message content".
The data comes amid heightened concerns on privacy following revelations that the NSA is scooping up vast amounts of data from the internet and mobile phones in the US and around the world.
Calabrese said the cell data underscores a need for reform "that updates our outdated privacy laws by requiring law enforcement to get a probable cause warrant before service providers disclose the contents of our electronic communications to the government".
"Anything less is unnecessarily invasive and un-American."