That's the allegation contained in a class action lawsuit, and it was reported by no less than the New York Times in 2007.  Business Insider noted this and other troubling information on the possible magnitude of NSA spying on Americans.

Over the weekend James Risen and Eric Lichtblau of The New York Times - who won a Pulitzer Prize in 2005 for this story on the NSA gaining the cooperation of U.S. telecommunications companies to obtain backdoor access to customer data