Nearly two years after NSA contractor Edward Snowden leaked thousands of pages of documents about highly classified government surveillance programs to journalists, intelligence officials continue to claim that his disclosures have caused grave damage to national security.

"It has had a material impact on our ability to generate insights as to what terrorist groups around the world are doing," NSA Director Michael Rogers said of Snowden's leaks at a conference Monday. "Anyone who thinks this has not had an impact… doesn't know what they are talking about."

But neither Rogers nor any other US government official has supported their catastrophic assessments with specific details about the damage Snowden allegedly caused. They say doing so would erode relations between the US and its allies, and reveal details about the US government's intelligence collection activities, which remain classified.

In response to a Freedom of Information Act (FOIA) lawsuit, the Defense Intelligence Agency (DIA) recently released to VICE News more than 100 pages of internal reports prepared by a task force made up of two dozen DIA analysts that examined the alleged damage to national security resulting from Snowden's leaks.

But with the exception of some subheadings, the DIA redacted every page of its internal assessments.

Some of the DIA's redacted documents provided to VICE News in response to a FOIA lawsuit. (Additional documents below)

Those subheadings included "assessment," "talking points," "compromised information," "background" and "recommendations." The reports, drafted between September 2013 and April 2014, were used by the "leadership" of the Department of Defense (DOD) to "mitigate the harm caused to national security," according to a declaration signed by the head of DIA's FOIA office, Aleysia Williams.

"The Task Force is evaluating how the disclosure of certain classified information exposes Intelligence Community sources and methods," Williams said, noting that if the agency were forced to disclose any of the substantive information contained in the 112 documents that make up the reports, the results would be disastrous.

She added that the task force reports are "compartmentalized" and only accessible to task force members, who must sign a nondisclosure agreement and "agree to additional security in order to access the records for mission purposes." Williams' declaration was filed in US District Court in Washington, DC, where the government is arguing that VICE News's FOIA lawsuit seeking documents related to the Snowden damage should be dismissed.

The DIA, which provides military intelligence to the DOD, summarized the task force's work in a 39-page report dated December 18, 2013 and titled "DoD Information Review Task Force-2: Initial Assessment, Impacts Resulting from the Compromise of Classified Material by a Former NSA Contractor." I obtained a copy of the heavily redacted report last year, which concluded that "the scope of the compromised knowledge related to US intelligence capabilities is staggering."

But explicit details about the alleged damage Snowden caused, identified in the 39-page report as "grave," were omitted from that document as well. In fact, the existence of the DIA's report had been unknown until the White House secretly authorized the declassification of select portions of it so two Republican lawmakers could undercut the media narrative painting Snowden as a heroic whistleblower.

"This report confirms my greatest fears — Snowden's real acts of betrayal place America's military men and women at greater risk," House Intelligence Committee Chairman Mike Rogers (who shares the same name as the current NSA director) said in a statement in January 2014. "Snowden's actions are likely to have lethal consequences for our troops in the field."

Rogers did not provide evidence for his claims. But the message was clear: The Obama administration has authorized leaks of its own internal reports about Snowden for political purposes, but any attempts by journalists to dig deeper would constitute a national security threat. Gene Barlow, a spokesman for the National Counterintelligence and Security Center, told VICE News that any "open discussion of the specific damages could further compromise classified information, operations, and various sources and methods involved in intelligence activities — as well as educate our adversaries in the process."

"As the Director of National Intelligence has stated, terrorists and other adversaries of this country are going to school on US intelligence sources methods and trade craft, and the insights that they are gaining are making our job much, much harder," Barlow said.

The government's excessive secrecy extends to other Snowden-related documents as well. The DIA said it had identified 109 documents totaling 859 pages that "refer" to the 39-page damage assessment. Those documents may include, for example, emails in which officials discussed the report. DIA withheld every page, citing national security concerns and other allowed exemptions to FOIA requests.

Steve Aftergood, the director of the Project on Government Secrecy at the Federation of American Scientists, who reviewed the recent documents obtained by VICE News, said the DIA is taking a "broad interpretation of law and classification policy in order to withhold as much as it can."

"This might be a good legal tactic, but it is disappointing in every other respect," Aftergood said. "It is a missed opportunity for the agency to explain, at least in general terms, what sorts of damage it believes that Snowden did. It's hard to understand why DIA can't say as much, or more."

The DIA did, however, reveal some details about the nature of the task force reports and the documents Snowden leaked that extend beyond government surveillance programs. In a separate declaration, David Leatherwood, the DIA's director of operations, said the task force reports contain details about:

•Military plans, weapons systems, or operations

•Foreign government information, intelligence activities (including special activities), intelligence sources, or methods or cryptology

•Foreign relations or foreign activities of the United States, including confidential sources

•Scientific, technological, or economic matters relating to national security

•United States government program for safeguarding nuclear materials or facilities

•Vulnerabilities or capabilities of systems, installations, infrastructures, projects, plans, or protection services relations to national security

•The development, production, or use of weapons of mass destruction

"The critical part of the task force's mandate was to figure out what harm was done to national security by the unlawful disclosure of this information," Leatherwood said. "To accomplish this goal, the reporting of the task force focuses entirely on identifying the magnitude of the harm. Much of that reporting, for very legitimate reasons, remains classified. The Department of Defense and the United States Intelligence Community must know what damage has been done before certain efforts to prevent future harm can be taken."

Leatherwood said DIA also classified references to newspaper articles about classified surveillance programs revealed by Snowden.

"Confirmation that these specific newspaper articles contain classified information through the release of these references under the FOIA would cause harm to national security by offering validation that the stolen information is classified," he said.

The government, in a 35-page motion asking a judge to dismiss the FOIA case, provides a breakdown of exactly how many task force documents relate to categories identified by Leatherwood. He said the task force reports are essentially guidelines that DOD and "affected agencies" use "to determine the level of harm caused and the order in which the various potential harms should be prioritized."

On Monday, Snowden participated in a Reddit "Ask Me Anything" chat with the recipients of his leaks — journalists Glenn Greenwald and Laura Poitras (the evening before, she won an Academy Award for her documentary on Snowden). During the AMA, Snowden said that if he could have done anything differently, he would have "come forward sooner."

"Had I come forward a little sooner, these programs would have been a little less entrenched, and those abusing them would have felt a little less familiar with and accustomed to the exercise of those powers," he said.

Follow Jason Leopold on Twitter: @JasonLeopold