Washington, May 7 (IANS): US federal judges ruled on Thursday that the National Security Agency's (NSA) bulk collection of telephone records of millions of Americans goes beyond what the Congress authorised in the 2001 Patriot Act.

The decision, which will have no immediate effect on the NSA programme, came from a three-judge panel of the 2nd US Circuit Court of Appeals in New York that was hearing a suit filed by the American Civil Liberties Union (ACLU), Efe news agency reported.

While the ACLU challenged NSA's actions on constitutional grounds, the appellate judges limited themselves to evaluating whether the collection of phone records was carried out in accord with the provisions of the Patriot Act, the law hurriedly passed by Congress following the terrorist attacks of September 11, 2001.

The government, under the administrations of both George W. Bush and Barack Obama, has maintained that NSA's collection of the external details of phone calls -- known as "metadata" -- was legal under Section 215 of the Patriot Act.

The appellate panel, however, found that Section 215, "cannot bear the weight the government asks us to assign to it, and that it does not authorise the telephone metadata programme".

"If Congress chooses to authorise such a far-reaching and unprecedented programme, it has every opportunity to do so, and to do so unambiguously," Circuit Judge Gerald Lynch wrote.

Section 215 expires at the end of June and Congress is currently considering whether to renew it unchanged, amend it or allow the provision to lapse.

The metadata collection and other massive electronic spying initiatives were revealed in the summer of 2013 by former US intelligence contractor Edward Snowden.

Last year, Obama proposed a plan that would require telephone companies to retain customers' calling records for 18 months and allow NSA to obtain access to the data via warrants issued by the Foreign Intelligence Surveillance Act (FISA) court.