The head of U.S. intelligence released new details on Saturday about the federal government's secretive program to monitor Internet users.
Director of National Intelligence James Clapper denied that the program, called PRISM, "unilaterally" obtains information from the servers of U.S. Internet companies.
"PRISM is not an undisclosed collection or data mining program," Clapper said in a statement. "It is an internal government computer system used to facilitate the government's statutorily authorized collection of foreign intelligence information from electronic communication service providers under court supervision, as authorized by Section 702 of the Foreign Intelligence Surveillance Act (FISA)."
He said that the Internet companies provide user data to the National Security Agency only after receiving an order approved by a secret FISA court.
Those courts only approve information requests if there is a "foreign intelligence purpose" and the target is "reasonably believed" to be outside of the United States, Clapper said.
"In short, Section 702 facilitates the targeted acquisition of foreign intelligence information concerning foreign targets located outside the United States under court oversight," he said. "Service providers supply information to the Government when they are lawfully required to do so."
Google, Facebook, Microsoft and other Internet companies vehemently denied news reports on Thursday that they allow the NSA to tap directly into their servers to mine their users' data.
The PRISM program reportedly gives the government access to the contents of users' emails, video chats, photographs and other information.
"Facebook is not and has never been part of any program to give the US or any other government direct access to our servers," Facebook CEO Mark Zuckerberg said in a blog post.
But the Internet companies have acknowledged that they are required to turn over user data in response to FISA court orders. The companies are barred from discussing or even acknowledging the existence of the orders.
Clapper said the FISA courts require certain "targeting and minimization procedures" to limit the amount of information incidentally collected about people in the United States.
His office has provided Congress with "exhaustive semiannual" reports on its activities, Clapper said.
He claimed the program has provided "insight into terrorist networks and plans," has helped to combat cyber attacks and has "significantly contributed to successful operations to impede the proliferation of weapons of mass destruction and related technology."
In a separate statement on Saturday, Clapper blasted news organizations for "reckless" disclosures of classified information.
"In a rush to publish, media outlets have not given the full context–including the extent to which these programs are overseen by all three branches of government–to these effective tools," he said.
He said he cannot reveal too much detail about PRISM without giving the nation's enemies a “playbook” of how to avoid detection.
But he said he decided to declassify some information about the program to "dispel some of the myths and add necessary context" to the news reports.
--This report was updated at 5:50 p.m.