Gen. Keith Alexander was asked about the report during an on-stage interview at a conference on cybersecurity hosted by Bloomberg Government.
"Not to my knowledge, that's never happened," Alexander said.
The Washington Post report, the latest product of the disclosures of former government contractor Edward Snowden, described a program dubbed MUSCULAR through which the NSA and the British spy outfit GCHQ have been tapping into the fiber-optic cables that run between the companies' overseas data centers and copying the flow of data.
Alexander, who said he was unfamiliar with the report, recalled the media coverage of the earlier Snowden revelation of the NSA's PRISM program to obtain emails and electronic communications from Internet companies, describing reports that characterized the NSA as having opened up a "back door" the firms' servers as "factually incorrect."
"This is not NSA breaking into any databases. It would be illegal for us to do that. And so I don't know what the report is, but I can tell you factually, we do not have access to Google servers, Yahoo servers," he said. "We are not authorized to go into a U.S. company's server and take data. We have to go through a court process for doing that."
Asked whether that meant that whenever the NSA reviews data from U.S. Internet companies, that information was obtained through a court order, Alexander replied: "That's correct."
But the program described in the Post report operates outside of the United States, where the NSA is unfettered by many of the constraints on its domestic operations. "Such large-scale collection of Internet content would be illegal in the United States, but the operations take place overseas, where the NSA is allowed to presume that anyone using a foreign data link is a foreigner," the paper reported.
So where the PRISM program operates under the oversight of the Foreign Intelligence Surveillance Court, there appears to be no such legal check on MUSCULAR, which is said to operate on a vast scale. In one 30-day period earlier this year, the NSA reportedly collected more than 180 million records.
The latest allegations are likely to further erode confidence overseas in the privacy protections in place at U.S. technology firms. Many cloud providers have warned that foreign businesses and consumers have been growing wary of storing their data with U.S. firms, worrying that their information could be accessed by intelligence operatives working under the Patriot Act.
Those concerns have only been exacerbated by the Snowden revelations. Acknowledging that they face a deficit of trust, several tech companies, including Google and Yahoo, have been seeking authorization from the government to publish more information about the national security orders they receive from intelligence officials. The Justice Department has been resisting those requests.
Even still, those orders are the product of the FISA court, which, though it is often criticized for rubber-stamping the requests of the intelligence community, is nonetheless an established institution within the judicial system. The latest program to come to light describes a sophisticated and clandestine operation beyond the reach of the court, and carried out without any knowledge or cooperation of the companies.
Kenneth Corbin is a Washington, D.C.-based writer who covers government and regulatory issues for CIO.com. Follow Kenneth on Twitter @kecorb. Follow everything from CIO.com on Twitter @CIOonline, Facebook, Google + and LinkedIn.
Read more about government in CIO's Government Drilldown.
Join the CIO Australia group on LinkedIn. The group is open to CIOs, IT Directors, COOs, CTOs and senior IT managers.