Rights groups have challenged the US Drug Enforcement Administration (DEA) over what they claim is the illegal surveillance of international phone communications.
The lawsuit was filed by the Electronic Frontier Foundation (EFF) and Human Rights Watch, and claims that the surveillance by the DEA and the US Department of Justice is untargeted, without merit, excessive and unconstitutional.
"The DEA's programme of untargeted and suspicion-less surveillance of Americans' international telephone call records - information about the numbers people call, and the time, date and duration of those calls - affects millions of innocent people, yet the DEA operated the programme in secret for years," said EFF staff attorney Nate Cardozo.
"Both the First and Fourth Amendment protect Americans from this kind of overreaching surveillance. This lawsuit aims to vindicate Human Rights Watch's rights, and the rights of all Americans, to make calls overseas without being subject to government surveillance."
Reports suggest that the surveillance system was first used in the 1990s but was confirmed, and then 'suspended', only after the Snowden revelations.
The rights groups want to ensure that this suspension becomes a termination, and that any collected information is destroyed.
"Human Rights Watch often works with people in dire circumstances around the world. Our sources are sometimes in life or death situations, and speaking out can make them a target," said Dinah PoKempner, general counsel at Human Rights Watch.
"Who we communicate with, and when we communicate with them, is often extraordinarily sensitive, and it's information that we would never turn over to the government lightly."
Last year the US senate introduced the USA Freedom Act 2014, a set of proposals that could stop such collections. The EFF cautiously welcomed this move, but said that it is only one step in the right direction.
"The USA Freedom Act of 2014 is a real first step because it creates meaningful change to National Security Agency [NSA] surveillance right now, while paving the way for the public to get more information about what the NSA is doing," the EFF said.
"We believe that this legislation will help ensure that the NSA reform conversation in Congress continues, rather than shutting it down. That's why we urge Congress to support the Senate version of USA Freedom and pass it without any changes that will weaken its provisions."
The FBI and Department of Homeland Security are also named in the lawsuit, which is filed in California.
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