Facebook, Google, and Microsoft today called publicly on the U.S. government to allow them to reveal statistics on how much intelligence agencies tap into their data.

The three were among nine Internet companies named last week in leaked slides about an NSA surveillance program called PRISM. Their statements may be a sign that the companies worry about being tainted by public concerns over the scope of the surveillance programs. Up to now the companies’ responses to the leaks had been limited to carefully worded, selective denials that they knew of a program called PRISM or that the NSA had “direct access” to their data stores.

Blog posts by the CEOs of Facebook and Google last Friday avoided the bigger question of whether the NSA had any access at all to their users’ files, probably because the legal instruments used by the agency forbid those asked to hand over data from disclosing anything about the request. Today’s statements were much clearer and implicitly acknowledged that the NSA does access user data from the companies.

Google’s chief legal officer, David Drummond, noted in his blog post today that Google’s annual transparency report, which summarizes the number of law-enforcement requests for user data, has always omitted figures on Foreign Intelligence Surveillance Act requests such as those used by the NSA:

“We therefore ask you to help make it possible for Google to publish aggregate numbers of national security requests, including FISA disclosures—in terms of both the number we receive and their scope.”

Microsoft, which also publishes a transparency report, e-mailed a statement to Reuters that said:

“Permitting greater transparency on the aggregate volume and scope of national security requests, including FISA orders, would help the community understand and debate these important issues.”

Facebook has never published figures on data requests and started its statement today from chief consul Ted Ullyot with the somewhat dubious claim that being unable to disclose FISA requests was the reason why. Ullyot wrote that the U.S. government should allow companies to publish “information about the size and scope of national security requests we receive.” He added that “[we] look forward to publishing a report that includes that information.”

Taken together, the statements from Google, Facebook, and Microsoft suggest that the companies are tired of taking flak for their involvement in surveillance programs that current U.S. law prevents them from resisting or even talking about. However, it’s fair to ask why the three have not made similar public statements before, given that the laws that allow the operation of programs like PRISM have been on the books for years.