Microsoft and Google have both announced intentions to sue the US government over their right to publish details about user data requests.
The tech giants filed suits in a US federal court in June, arguing a right to make public more information about user data requests made under the auspices of the Foreign Intelligence Surveillance Act (FISA).
The technology giants agreed six times to extend the deadline for the government to respond to the lawsuits, the Microsoft\’s general counsel, Brad Smith, wrote in a blog post.
"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 posted on the blog.
"To followers of technology issues, there are many days when Microsoft and Google stand apart," 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 tech sector has been pushing for greater transparency of government data requests as companies seek to shake off the concerns about their involvement in vast secret US surveillance programmes revealed by former spy contractor Edward Snowden.
US officials on Thursday said they would begin publishing annual tallies of national security requests for Internet user data, but that step is not enough, according to Smith.
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.
US authorities insist the surveillance programmes are entirely lawful and have helped thwart dozens of terror attacks.