Facebook and Microsoft for the first time on Friday said they had gotten data requests from the U.S. government under the Foreign Intelligence Surveillance Act (FISA), but added that the government did not permit them to provide specific figures.

Instead, the government allowed the companies to release only broad numbers with no breakdowns. Over the last six months of 2012, Facebook said it had received as many as 10,000 requests from local, state and federal agencies, which affected as many as 19,000 accounts. Microsoft said it received between 6,000 and 7,000 requests, affecting as many as 32,000 accounts.

The companies said some of the requests were for terrorist investigations. Others, however, were from sheriffs asking for data to locate missing children or from federal marshals tracking fugitives. From these statements, it was impossible to ascertain the scale of the FISA requests made by the National Security Agency.

The companies said they have been pressing the U.S. government for permission to talk more openly about the data requests since The Washington Post and The Guardian newspapers reported on a secret surveillance program called PRISM that was aimed at tracking terrorist activities. The reports cited an NSA PowerPoint presentation that said the agency connected directly to the servers of Facebook, Google, Microsoft and other Silicon Valley giants. Another NSA document described the program differently, however.

Facebook and other tech companies have vigorously denied giving the government direct access to their servers.

A letter that Google sent to Attorney General Eric Holder and FBI Director Robert Mueller has prompted discussions with federal officials about whether Google can release more detailed information, said a person familiar with the talks.