U.S. District Judge Richard Leon declared Monday that the "government's once-secret collection of domestic phone records is unconstitutional, setting up likely appeals and further challenges to the data mining, revealed by classified leaker Edward Snowden," CNN reported. Leon said the NSA's collection of metadata (or "phone records of the time and numbers called without any disclosure of content") has violated privacy records.

"I cannot imagine a more 'indiscriminate' and 'arbitrary invasion' than this systematic and high-tech collection and retention of personal data on virtually every citizen for purposes of querying and analyzing it without prior judicial approval. Surely, such a program infringes on 'that degree of privacy' that the Founders enshrined in the Fourth Amendment," said Leon.

Andrew Ames, a spokesman for the U.S. Justice Department, said attorneys were reviewing the ruling.

"We believe the program is constitutional, as previous judges have found," Ames said.

Snowden, who is in self-imposed exile in Russia, issued a statement through reporter Glenn Greenwald, that he was convinced the program would not survive a court challenge.

"A secret program authorized by a secret court was, when exposed to the light of day, found to violate Americans' rights. It is the first of many," Snowden said. Greenwald believes that this ruling has vindicated the leaker's mission of uncovering the NSA supposed unlawful invasion of citizen's private records.

"I think it's not only the right, but the duty of an American citizen in Edward Snowden's situation to come forward, at great risk to himself, and inform his fellow citizens about what it is their government is doing in the dark that is illegal," Greenwald told CNN's "Anderson Cooper 360" on Monday night.

"The bulk collection of Americans' phone records conflicts with Americans' privacy rights under the U.S. Constitution and has failed to make us safer," added Colorado Senator Mark Udall.

The sentor called on Congress to pass legislation he proposed to "ensure the NSA focuses on terrorists and spies - and not innocent Americans."