WASHINGTON, May 11 (Xinhua) -- The U.S. National Security Agency (NSA) has been secretly collecting the phone call records of tens of millions of Americans, using data provided by three major telecommunication companies, the USA Today newspaper reported on Thursday.

    The NSA program reaches into homes and businesses across the nation by amassing information about the calls of ordinary Americans -- most of whom aren't suspected of any crime, the report said.

    The program does not involve the NSA listening to or recording conversations, but the spy agency is using the data to analyze calling patterns in an effort to detect terrorist activity, sources were quoted as saying.

    "It's the largest database ever assembled in the world," and the NSA's goal was "to create a database of every call ever made" within the nation's borders, one source told the newspaper.

    The three telecommunications companies, AT&T, Verizon and BellSouth, are working under contract with the NSA, which launchedthe program in 2001 shortly after the September 11 terrorist attacks, according to the report.

    Bush George W. Bush acknowledged last year that he had authorized the NSA to eavesdrop, without court warrants, on international calls and international e-mails of people suspected of having links to terrorists when one party to the communication was in the United States.

    Warrants have also not been used in the NSA's efforts to createa national call database, the report said.

    Verizon, BellSouth and AT&T are the nation's three biggest telecommunications companies, providing local and wireless phone service to more than 200 million customers.

    The NSA, a secret spy agency created during the Korean War in 1952, is charged with protecting the United States from foreign security threats and collects intelligence information by intercepting international communications. Enditem