A coalition of technology companies and civil liberties groups on Thursday will call on President Obama and congressional leaders to dramatically expand the amount of information reported publicly about U.S. government surveillance efforts.

The request, to be made in a letter with more than 50 signatories, is the most sweeping and cohesive push to bring more accountability to electronic government eavesdropping in the aftermath of revelations about the National Security Agency’s collection of user data.

The letter will call on the government to remove restrictions that keep companies from reporting the number of surveillance requests they receive from U.S. officials citing national security grounds. Several companies already produce regular “transparency reports” listing information when the requests relate to criminal investigations.

The expected signatories, including Microsoft, Google and the Electronic Frontier Foundation, also will call on the government to issue its own regular reports offering an overall account of the information it is gathering from telecommunication and technology companies, which have been stung by portrayals of their cooperation with NSA data requests.

“This information about how and how often the government is using these legal authorities is important to the American people, who are entitled to have an informed public debate about the appropriateness of those authorities and their use, and to the international users of U.S.-based service providers who are concerned about the privacy and security of their communications,” said the draft version of the letter, which was obtained by The Washington Post. It is due for public release Thursday morning.

The Center for Democracy & Technology, a Washington-based nonprofit group, organized the letter, which attracted a wide range of support, including trade groups, press freedom groups and more than 20 companies.

The composition of the coalition — including tech firms and privacy groups that sometimes criticize them — underscores the broad concern generated by revelations about NSA surveillance programs.

“The American people lack basic information about the scope of the government’s surveillance of the Internet, information that many companies would eagerly share with their users if only they weren’t gagged by the government,” said Kevin S. Bankston, senior counsel for the Center for Democracy & Technology. “All we’re asking for in this letter is the same type of general numerical information that has been published about law enforcement surveillance for years.”

The public push comes amid rising concern on Capitol Hill about the secretive collection of phone and Internet data, especially when it involves U.S. citizens.

House members expressed serious concern about NSA programs in a hearing Wednesday. Reps. Zoe Lofgren (D-Calif.) and F. James Sensenbrenner Jr. (R-Wis.) sent a letter Tuesday asking Attorney General Eric H. Holder Jr. and Director of National Intelligence James R. Clapper Jr. to give companies more latitude to publicly disclose the number of surveillance requests.

“The U.S. government’s refusal to allow companies to release figures reflecting these requests prevents them from taking basic steps to preserve public confidence in U.S. Internet services,” the letter said.

Technology companies have scrambled for more than a month to protect their reputations amid revelations about the NSA’s data collection through its PRISM program, which, according to slides published by The Post and Britain’s Guardian newspaper, had extensive access to user data from Google, Facebook, Microsoft, Apple, Yahoo and other companies.

The companies have disputed those portrayals, saying they exaggerate collection efforts that are legal and limited. The firms also have bridled against government restrictions on their ability to report the extent of government surveillance requests made on national security grounds.

Google and Microsoft, which for years have produced regular reports on government information requests, last month asked the Foreign Intelligence Surveillance Court for permission to publish approximate numbers of requests they receive on national security grounds.

Thursday’s letter goes further still. It asks that tech and telecommunications companies be able to report on the number of requests they receive under Section 215 of the Patriot Act, under Section 702 of the Foreign Intelligence Security Act Amendments Act and from statutes covering national security letters. The letter also requests that the companies be able to say how many users, accounts or devices are covered by those requests.

Absent among the signers are the major telecommunications companies, which for decades have complied with a broad range of government surveillance activities.

In addition to the collection of user data through PRISM, the NSA also accesses data through fiber-optic cable networks that carry most of the world’s intercontinental phone and Internet traffic. That effort is described as “Upstream” collection in one of the NSA slides previously published by The Post.

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