The newspaper USA Today has gone back on claims that two top phone companies co-operated with a US government programme to monitor terror activity.
Calls from both landlines and mobiles are reportedly being logged
It said it could not establish that BellSouth or Verizon had given calling records to the National Security Agency (NSA), as it reported in May.
However US Today also quotes unnamed members of Congress as saying the NSA has been collecting data on calls.
BellSouth said it had never provided any of its record to the NSA.
President Bush refused to confirm or deny the existence of the programme.
He said he had authorised intelligence gathering in the wake of 9/11, adding that the activities were "lawful".
It its original story on May 11, USA Today said the three biggest US phone companies - AT&T, BellSouth or Verizon - had handed over call records to the NSA since 2001.
The report did not claim that the government was listening in on phone calls.
AT&T tight lipped
In a "Note to our readers" in Friday's issue, the newspaper said: "Based on reporting after the May 11 article, USA Today has now concluded that while the NSA has built a massive domestic call records database... the newspaper cannot confirm that BellSouth or Verizon contracted with the NSA" to provide data.
In an accompanying story, the paper said AT&T had neither confirmed nor denied the paper's original report.
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
Agency as a whole is so secretive its initials are said to stand for "No Such Agency"
The latest story also quoted five members of congressional intelligence committee in Congress as saying they had learnt that neither BellSouth nor Verizon had co-operated with the programme.
However it added that the unnamed lawmakers had confirmed that the database exists.
In its note to readers, USA Today promised to "continue to report on the content and scope of the database".
BellSouth issued its own statement on Friday, saying the NSA had never contacted it and the firm had "never supplied customer calling records to the NSA".
Experts disagree about whether the government has the authority to demand the data it is allegedly compiling.
USA Today's allegations followed reports in The New York Times last 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.