US phone records data 'critical'
The White House has said a court order allowing the United States government to secretly collect millions of American citizens' telephone records is a critical tool to fight security threats.
White House spokesman Josh Earnest said he cannot discuss classified information but the court order in question allows the intelligence community to know when terrorists or suspected terrorists are engaging in dangerous activities.
He said that is particularly true for people located in the US.
He said the order does not allow the government to listen in on calls, but only includes details like telephone numbers.
Mr Earnest said there is a robust legal regime overseeing the programme and that Congress has been fully briefed.
Disclosure of the phone records was first reported by The Guardian newspaper and confirmed by Democratic Senator Dianne Feinstein.