US President George W Bush has used his weekly radio address to launch a strong defence of his administration's domestic surveillance programme.
It follows claims the phone records of tens of millions of Americans are being collected by a US intelligence agency.
Mr Bush stressed that all intelligence activities he authorised were "lawful" and "strictly target" al-Qaeda.
"The privacy of all Americans is fiercely protected in all our activities," he insisted.
"The government does not listen to domestic phone calls without court approval. We are not trawling through the personal lives of millions of innocent Americans."
WHAT IS THE NSA?
US government intelligence service founded as a code-breaking agency in 1952
Intercepts communications using satellites and bugs
Said to be largest employer of mathematicians in the US
Budget and staff size classified
An agency as a whole so secretive its initials are said to stand for "No Such Agency"
Mr Bush has not confirmed or denied a report in the USA Today newspaper that the country's three biggest phone companies have been handing over call records to the National Security Agency (NSA) since 2001.
A former director of the agency - Gen Michael Hayden - is now Mr Bush's nominee to become the next head of the CIA.
In his radio address, the president also urged the Senate to approve the nomination quickly, saying Gen Hayden is "supremely qualified" for the job.
Congressmen are expected to use the confirmation hearings to probe the USA Today allegations further.
'Largest ever database'
The newspaper reported last Thursday that the NSA database had used phone records provided by AT&T, Verizon and BellSouth.
The report does not claim the government listened in on phone calls.
But it cites an unnamed source as saying the NSA has used data on telephone calls to build "the largest database ever assembled in the world".
Together the three phone firms serve more than 200 million customers. They told USA Today they had not broken any laws.
The New York Times reported in December that the NSA was eavesdropping on phone calls made between terror suspects inside the US and abroad.
The report caused controversy because many legal experts believe the government needs explicit permission from a special court to do so - which it did not obtain.