In a statement, Facebook General Counsel Ted Ullyot said that the company had received 9,000 to 10,000 requests from US federal, state and local authorities in the six months prior to December 31, 2012. The requests affected between 18,000 and 19,000 user accounts. A deal with the US government allowed Facebook to include national-security-related requests in the tally for the first time.
"We hope this helps put into perspective the numbers involved and lays to rest some of the hyperbolic and false assertions in some recent press accounts about the frequency and scope of the data requests that we receive," a statement on Facebook read.
The Guardian newspaper revealed PRISM earlier this month thanks to an exclusive meeting with a whistleblower. According to documents allegedly leaked by ex-CIA contractor Edward Snowden, the program gives the US government direct access to the servers of major Internet companies like Facebook, Google and Apple.
The disclosures of Prism, and related revelations about broad-based collection of telephone records, have triggered widespread concern and congressional hearings about the scope and extent of the information-gathering.
Microsoft publishes data
Microsoft later released its own data with national-security-related requests also included. For the same six-month period, Microsoft received between 6,000 and 7,000 criminal and national security warrants, said the company's deputy general counsel, John Frank. The requests concerned between 31,000 and 32,000 consumer accounts.
Google announced late on Friday that that the company had begun negotiations with the government over whether it could only publish a combined figure for all requests.
EU seeks 'more info' on PRISM
European officials have voiced concern that PRISM has been used to monitor EU citizens, a potential violation of the 27-member bloc's data protection rules.
EU Home Affairs Commissioner Cecilia Malmstrom and Justice Commissioner Viviane Reding established the agreement Friday, after meeting with US Attorney General Eric Holder in Ireland. Malmstrom confirmed the news on Twitter.
"Agreed with the US in Dublin to set up a transatlantic expert group to receive more info on PRISM and look at the safeguards," she wrote.
In Germany, ministers have questioned Internet companies over what information they provide governments.
mkg/slk (AFP, Reuters, dpa, AP)