Apple (Fortune 500) said it had received between 4,000 and 5,000 requests, covering between 9,000 and 10,000 accounts or devices, from federal, state and local authorities. ,
Some of the requests were related to national security matters, but most were made by police investigating crimes, searching for missing persons or trying to prevent suicide, according to the company.
Apple's revelation follows the leaking by American computer analyst Edward Snowden of details of a U.S. government system for monitoring millions of emails, photos, search histories and other data from major telecommunications and technology firms.
Snowden's leaks have sparked a furious debate about the scale and scope of the National Security Agency surveillance program, which dates back to the days after the 2001 al Qaeda attacks on New York and Washington. It has also raised questions about the role tech companies play.
Apple said it first heard of the program -- known as Prism -- on June 6. Since then, like other tech companies, it had sought U.S. government permission to report how many requests it receives and how it handles them. It said it does not provide direct access to its servers.
"Regardless of the circumstances, our legal team conducts an evaluation of each request and, only if appropriate, we retrieve and deliver the narrowest possible set of information to the authorities," the company said in a statement.
"In fact, from time to time when we see inconsistencies or inaccuracies in a request, we will refuse to fulfill it."
Facebook ( and )Microsoft (Fortune 500)have also , published details of the extent of their involvement in recent days. Facebook said it received between 9,000 and 10,000 requests in the last half of 2012, targeting between 18,000 and 19,000 accounts.
Over the same period, Microsoft received between 6,000 and 7,000 criminal and security warrants, subpoenas and orders affecting as many as 32,000 customer accounts.
Apple said there were certain categories of information it was unable to provide to law enforcement officials because it didn't record them. Such data includes iMessage or FaceTime conversations, which Apple said were protected by end-to-end encryption so that no one but the sender or receiver can see or read them.
"Apple cannot decrypt that data. Similarly, we do not store data related to customers' location, Map searches or Siri requests in any identifiable form," Apple said.
Reporting all law enforcement requests together makes it hard to single out those made for national security reasons.
Google (Fortune 500), which publishes a , transparency report detailing requests from governments worldwide, has said it wants to be able to break out numbers of national security requests separately.
The spying allegations threatened to cast a shadow over a meeting of G-8 leaders beginning Monday in the U.K. after the Guardian newspaper published a new report based on documents provided by Snowden. The paper claimed that Britain's electronic intelligence agency monitored delegates' phones and tried to capture their passwords during an economic summit in 2009.
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