The secret US Foreign Intelligence Surveillance Court has extended the power of the NSA to collect citizens’ telephone records for three more months.

Director of public affairs Shawn Turner confirmed the court has renewed the NSA phone collection programme by allowing them to gather metadata from phone companies.

"The intelligence community continues to be open to modifications to this programme that would provide additional privacy and civil liberty protections while still maintaining its operational benefits," Turner said.

Earlier, similar orders were occasionally issued to individual telephone firms, while the latest order covers all telecom companies from which metadata had been gathered as per recent previous court approvals.

The latest disclosure comes following two clashing legal ruliings on NSA surveillance activities, including the December ruling of Judge Richard Leon which criticised the NSA programme, which was later contradicted in a separate case by Judge William Pauley.

Last month, US civil liberties groups including American Civil Liberties Union (ACLU) and Yale University’s Media Freedom and Information Access Clinic sued the US government over details about NSA’s overseas snooping activities.

Recent reports have revealed that the NSA is also funding the development of a new quantum computer, which would enable the agency to crack encryption codes much faster.