(Washington) The apparent leak of classified U.S. documents, including those related to Ukraine and most of which appear genuine, poses a “very serious” risk to U.S. national security, the Pentagon said Monday.

Having these documents circulating online poses “a very serious national security risk and has the potential to fuel misinformation,” U.S. Department of Defense spokesman Chris Meagher told reporters.

“We continue to investigate how this happened, as well as the extent of the problem. Steps have been taken to further analyze how this type of information was distributed and to whom,” he added.

A steady stream of photographs of classified documents have been discovered on Twitter, Telegram, Discord and other sites in recent days; although some may have circulated online for weeks before attracting media attention.

Many of them are no longer available on the sites where they originally appeared, and US authorities are reportedly working to have them all removed.

Defense Secretary Lloyd Austin himself was not made aware of the problem until the morning of April 6 — the day the leak was revealed later that day by The New York Times — the report said. Pentagon spokesman.

Many of these documents concern the war in Ukraine: one takes stock of the state of the conflict at the beginning of March, others evoke the situation on specific fronts, such as Bakhmout, or the anti-aircraft defenses of Kyiv.

Some also seem to indicate that the United States is spying on some of its allies: one mentions that leaders of the Mossad, the Israeli intelligence service, have allegedly defended the demonstrations against the controversial reform of the judicial system in Israel.

US officials have contacted Washington allies about the matter, and relevant parliamentary committees have been briefed, the Pentagon had earlier said.

Meagher declined to comment Monday on the authenticity of the documents, saying a department team was working to determine if they were genuine, but noted that the photos released appeared to contain sensitive information.

“Photos appear to show documents in a format similar to that used to provide daily updates to our senior Ukraine and Russia-related operations, as well as other intelligence updates,” he said. he said, but some “seem to have been edited.”

At least one of the documents seems to have been altered to suggest that Ukraine suffered greater losses than Russia, when the supposed original said the opposite.

The consequences of these leaks could be significant, even deadly for US intelligence sources.

“The release of classified and sensitive information can not only have enormous consequences for our national security, but also lead to people’s death,” the spokesperson said.

The Justice Department has opened a criminal investigation.