The letters go on to say that they will not be releasing further information to the public, citing national security concerns.
Public discussion of the highly classified uses of Section 215 authority, including the bulk collection program conducted thereunder, is problematic because it would expose sensitive sources and methods involved in this critical intelligence collection activity. Because we are concerned that disclosure would cause serious damage to national security, we cannot disclose publicly that Section 214 is used for bulk collection of telephony metadata. We do agree, however, that it is important that Members of Congress have access to information about this program, as well as a similar collection program conducted under the pen register/trap and trace authority of FISA, when considering reauthorization of the expiring USA PATRIOT Act provisions.
The letter does say that the Department of Justice has "worked with the Intelligence Community to prepare a document that describes these two collection programs" and the authorities under which they operate. However, many members of Congress have expressed shock at the extent of surveillance and do not believe they were adequately informed about NSA actions. For instance, Rep. Jim Jordan (R-Ohio) claims to have been surprised by the revelations while Rep. Justin Amash (R-Mich.) described trying to get straight answers out of intelligence hearings as a frustrating game of 20 questions. Even Patriot Act author Rep. Jim Sensenbrenner (R-Wis.) believes there was a "failure of oversight."