The Twitter headquarters in San Francisco, California / Getty Images

Microblogging site is fighting for the right to publish statistics on data requests

Twitter is suing the US Government, claiming it is violating the social network’s freedom of speech by stopping it fully reporting on the scope of surveillance.

American laws restrict what providers like Twitter can disclose about the number of official security requests received demanding private account information.

National Security Letters and court orders citing the Foreign Intelligence Surveillance Act are commonly used to force websites to hand over data.

Ben Lee, Twitter’s vice president, said: “It’s our belief that we are entitled under the First Amendment to respond to our users’ concerns and to the statements of US Government officials by providing information about the scope of US Government surveillance – including what types of legal process have not been received.

“We should be free to do this in a meaningful way, rather than in broad, inexact ranges.”

Current rules do not allow the exact number of legal requests to be published, only permitting broad estimates within the hundreds or thousands.

On Wednesday, a lawsuit was filed with a court in San Francisco, where Twitter is based, seeking to publish its full report on transparency including information on Government requests.

Edward Snowden's revelations led to calls for legal reforms

The company said it had been prevented publishing parts of the report, compiled in response to users’ concerns, by the FBI and US Department of Justice.

The complaint filed against America’s Attorney General, the FBI and Department of Justice, reads: “The defendants’ position forces Twitter either to engage in speech that has been pre-approved by government officials or else to refrain from speaking altogether…

“These restrictions constitute an unconstitutional prior restraint and content-based restriction on, and government viewpoint discrimination against, Twitter’s right to speak about information of national and global public concern.”

Because most Twitter posts are public, the company claims it is not subjected to as many Government demands as other sites like Facebook.

The case comes as the US Court of Appeal considers the constitutionality of the “non-disclosure” provisions in the law governing National Security Letters.

The Snowden revelations provoked public anger at the NSA

Mr Lee said the company supported the USA Freedom Act being considered by the Senate, which would reform powers to covertly intercept online communications and allow Facebook, Twitter and other sites to be more transparent in the information they share.

Five technology companies including Facebook, Google and Microsoft won concessions earlier this year when the Justice Department relaxed restrictions on disclosing surveillance information.

Leaks by former National Security Agency (NSA) contractor Edward Snowden revealed the extend of digital spying across the US, Europe and in Britain.

Documents indicated that Britain’s communications agency GCHQ and the NSA used mobile phone apps including Angry Birds to access personal data as well as an array of covert online operations.