Tapped: Why Did Verizon and Bellsouth Issue Denials AFTER The Story Broke?

WHY DID VERIZON AND BELLSOUTH ISSUE DENIALS AFTER THE STORY BROKE? Here's another thing about the denials that doesn't quite add up. As we've seen, both Verizon and Bellsouth have more or less denied the USA Today story saying that the NSA has been secretly collecting their phone records. USA Today appears to be sticking to the story, though the paper's statement seems to carefully avoid a total commitment to it, instead saying that the paper's "confident" in its reporting.

But something doesn't quite make sense. Why are Verizon and Bellsouth only denying these allegations after the story broke?