Technology giants Google and Microsoft have teamed up for a legal battle seeking clarity on secret U.S. government requests for Internet user data after failed negotiations with the Obama administration.

The two companies filed suits in a federal court in June, arguing a right to disclose more information about user data requests made by the government under the controversial Foreign Intelligence Surveillance Act.

Their representatives met six times with US officials and agreed to extend the deadlines for the government to reply to the lawsuits, allowing time for negotiations that ended in failure, Microsoft general counsel Brad Smith said.

“We hoped that these discussions would lead to an agreement acceptable to all. While we appreciate the good faith and earnest efforts by the capable government lawyers with whom we negotiated, we are disappointed that these negotiations ended in failure,” Mr. Smith said in a blog post.

Setting aside their strategic competitiveness, the two Silicon Valley Internet bellwethers want to be able to provide users with better insight into what information the government gets its hands on.

“To followers of technology issues, there are many days when Microsoft and Google stand apart,” Mr. Smith said.

“But today our two companies stand together...We believe we have a clear right under the US Constitution to share more information with the public.”

The issue became highlighted after Edward Snowden, a former IT contractor at the National Security Agency (NSA), disclosed that the US authorities were tapping into Internet user data, sometimes using national security letters that bar companies from telling anyone about the requests.

Referring to the government’s recent decision to begin publishing the total number of national security requests for user data for the past 12 months and do so going forward once a year, Smith said such a decision represents a good start.

The public deserves and the Constitution guarantees more than this first step, he added.

Mr. Smith said over the past several weeks Microsoft and Google have pursued these talks in consultation with others across the technology sector.

“With the failure of our recent negotiations, we will move forward with litigation in the hope that the courts will uphold our right to speak more freely,” he said.

He said with a growing discussion on Capitol Hill, Congress will continue to press for the right of technology companies to disclose relevant information in an appropriate way, adding courts and Congress will ensure that their Constitutional safeguards prevail.

Mr. Smith said he believes it is vital to publish information that clearly shows the number of national security demands for user content, such as the text of an email.

“These figures should be published in a form that is distinct from the number of demands that capture only metadata such as the subscriber information associated with a particular email address,” he said.

“We believe it’s possible to publish these figures in a manner that avoids putting security at risk. And unless this type of information is made public, any discussion of government practises and service provider obligations will remain incomplete,” Mr. Smith said.

There has been a wave of legal action since revelations in the media about the PRISM program, believed to collect vast amounts of phone and Internet data as part of efforts to protect national security.

Internet companies have stated they release information only in response to specific court orders, and claim that reports about providing easy access to US authorities are exaggerated.