A unique and unusually productive relationship with AT&T has helped the US National Security Agency trawl through vast quantities of Internet traffic, much of it transmitted through networks located in the US, according to a media article published Saturday.

The cooperation involved a variety of classified programs that span decades, in one case more than 15 years before the September 11 terrorist attacks. In addition to providing the NSA with access to billions of e-mails flowing across its domestic networks, AT&T helped wiretap all Internet communications at the United Nations headquarters, which is, or at least was, an AT&T customer, according to the article, which was jointly reported and written by reporters from The New York Times and ProPublica. The article, which relied on NSA documents leaked by former agency contractor Edward Snowden, said that AT&T competitor Verizon participated in some of the same activities, but on a much smaller scale. One NSA document reminded officials to be polite when visiting AT&T sites since the arrangement was a "partnership, not a contractual relationship."

One of the oldest programs is dubbed Fairview and began in 1985. A separate program known as Stormbrew included Verizon and MCI, the former telecommunications provider that Verizon acquired in 2006. The NYT and ProPublica go on to paint AT&T as a particularly willing partner. The article stated:

In September 2003, according to the previously undisclosed N.S.A. documents, AT&T was the first partner to turn on a new collection capability that the N.S.A. said amounted to a “ ‘live’ presence on the global net.” In one of its first months of operation, the Fairview program forwarded to the agency 400 billion Internet metadata records — which include who contacted whom and other details, but not what they said — and was “forwarding more than one million emails a day to the keyword selection system” at the agency’s headquarters in Fort Meade, Md. Stormbrew was still gearing up to use the new technology, which appeared to process foreign-to-foreign traffic separate from the post-9/11 program. In 2011, AT&T began handing over 1.1 billion domestic cellphone calling records a day to the N.S.A. after “a push to get this flow operational prior to the 10th anniversary of 9/11,” according to an internal agency newsletter. This revelation is striking because after Mr. Snowden disclosed the program of collecting the records of Americans’ phone calls, intelligence officials told reporters that, for technical reasons, it consisted mostly of landline phone records. That year, one slide presentation shows, the N.S.A. spent $188.9 million on the Fairview program, twice the amount spent on Stormbrew, its second-largest corporate program.

It's not the first time AT&T has been accused of playing a crucial role in indiscriminant NSA surveillance involving US persons. In 2006, retired AT&T technician Mark Klein alleged in a federal lawsuit that he had seen NSA equipment installed in a secret room inside San Francisco central office AT&T used to route Internet communications. Klein said AT&T was giving the NSA access to traffic AT&T transmitted through peering agreements with other telecom companies.