The Defense Department is saying little about its efforts in response to a massive data leak that may prove to be the most dangerous disclosure of classified material since former National Security Agency Contractor Edward Snowden revealed intelligence secrets a decade ago.

The documents, which began appearing online in January, contain several highly damaging revelations, including how Ukraine could run out of air defense missiles by May. These documents also show the United States was able to provide the Ukrainians with intelligence about impending Russian attacks before they happened.

Other documents include a CIA intelligence report about Israel’s intelligence agency, the Mossad; and a secret report that top South Korean government officials were concerned the United States might provide Ukraine with artillery shells it had bought from South Korea.

Since the data leak became public on April 7, the Justice Department has launched a criminal investigation, and the U.S. government has begun an interagency effort to look at the consequences the leak poses to national security, said Chris Meagher, assistant to the secretary of defense for public affairs.

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Defense Secretary Lloyd Austin has established an effort that includes several defense officials and agencies to look at the potential consequences of the data leaks and to make sure the U.S. military is working closely with Congress along with U.S. allies and partners, Meagher told reporters on Monday.

Meagher declined to say which foreign governments U.S. government officials have spoken with recently over the data leak.

A Pentagon team is currently looking at pictures of documents that have appeared on social media to determine their authenticity, Meagher said at a Pentagon news conference.

“These photos appear to show documents similar in format to those used to provide daily updates to our senior leaders on Ukraine- and Russia-related operations, as well as other intelligence updates,” Meagher said. “Some of these images appear to have been altered.”

The documents are used by a variety of people within and outside the Department of Defense, said Meagher, who did not specify which government officials might have been privy to the leaked information.

“I’m not going to classify for you exactly the universe of people who have access to this material,” Meagher said. “I will just say that it is highly classified, sensitive material that people in DoD, certainly, and other aspects of the U.S. government use to inform their work.”  

Meagher would not say the level at which the documents were classified – such as top secret – and he declined to answer questions about what is in the documents themselves because they contain sensitive information, and the Justice Department has an ongoing criminal investigation into the data leak. He also declined to say how many documents may have been posted online.

The Pentagon is trying to determine if any other classified information may have been leaked, said Meagher, who cautioned the news media to be careful on how they reported on the leaked documents because disclosure of classified material “could lead to people losing their lives.”

“The Department of Defense is working around the clock to look at the scope and the scale of the distribution, the assessed impact, and our mitigation measures,” Meagher said. “We’re still investigating how this happened as well as the scope of the issue. There have been steps to take a closer look at how this type of information is distributed and to whom.”

When asked if the Pentagon has already taken steps to limit the circulation of classified information within the Defense Department, Meagher did not answer directly.

“Any distribution of highly sensitive, classified material is something that we take very seriously,” Meagher said. “And so, we’re taking this very seriously, and that’s why this has the full attention of the secretary and of this department.”

The intra-Defense Department effort to respond to the data leaks includes several organizations including public affairs, legislative affairs, the office of general council, the undersecretary of defense for policy’s office, the undersecretary of defense for intelligence and security’s office; the Joint Staff; and others, Meagher said.

Meagher repeatedly declined to say who at the Pentagon oversees this effort across so many Defense Department organizations.

“I’m just not going to get into more specifics of that,” Meagher said when a reporter pressed him to name who is leading the Defense Department effort.

The data leak is the latest example of classified information appearing online. Classified information about F-16s, F-15s, and British tanks has been posted by gamers on War Thunder forums. 

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