COURT : SURVEILLANCE PROGRAM ILLEGAL

San Francisco : Seven years after former NSA contractor Edward Snowden blew the whistle on the mass surveillance of America's telephone records, an appeal court has found the programme was unlawful - and that the US intelligence leaders who publicly defended it were not telling the truth.

In a ruling handed down on Wednesday, the US Court of Appeals for the Ninth Circuit said the warrant-less telephone dragnet that secretly collected millions of Americans telephone records violated the Foreign Intelligence Surveillance Act and could well have been unconstitutional.

Snowden, who fled to Russia in the aftermath of the 2013 disclosures and still faces US espionage charges, said on Twitter that the ruling was a vindication of his decision to go public with evidence of the National Security Agency's domestic eavesdropping operation.

''I never imagined that I would live to see courts condemn NSA's activities as unlawful and in the same ruling credit for me for exposing them,'' Snowden said in a message posted on Twitter.

Evidence that NSA was secretly building a vast database of US telephone records - the who, the how, the when, and the where of millions of mobile calls - was the first and arguably the most explosive of the Snowden's revelations published by the Guardian newspaper in 2013.

Up until that moment, top intelligence officials publicly insisted that NSA never knowingly collected information on Americans at all.

 After the programme's exposure, US officials fell back on the argument that spying had played a crucial role in fighting domestic extremism, citing in particular the case of four San Diego residents who were accused of providing aid to religious fanatics in Somalia.

US officials insisted that the four - Basaaly Saeed Moalin, Ahmed Nsir Taalil Mohamud, Mohamed Mohamud, and Issa Doreh were convicted in 2013 thanks to NSA's telephone record spying., but the Ninth Circuit ruled on Wednesday that those claims were ''inconsistent with the contents of the classified record''.

The ruling would not affect the convictions of Moalin and his fellow defendants; the courts ruled the illegal surveillance did not taint the evidence introduced at their trial.

Nevertheless, watchdog groups including the American Civil Liberties Union, which helped bring the case to appeal, welcomed the judges verdict on NSA's spy programme.

''Today's ruling is a victory for our privacy rights,'' the ACLU said in a statement. [Reuters]