More than 100 classified documents detailing U.S. national security secrets have been leaked on social media, purportedly exposing crucial intelligence on Ukrainian military operations in a breach that could be a boon to Russia.
The documents, believed to have come from within U.S. military and intelligence agencies, have been circulated on Twitter, 4chan, and Telegram, where they were spread by pro-Kremlin commentators, according to The Wall Street Journal.
The Pentagon acknowledged on Thursday that officials were looking into the leak, which experts say may be one of the most damaging breaches in decades.
The New York Times, which was the first to report on the leaks, says defense officials were already scrambling early Friday to determine the scale of the first batch of leaked documents when it was discovered that another batch had been released.
One unnamed official quoted by the Times called the breach “a nightmare for the Five Eyes,” as the documents concern secrets regarding not only Ukraine, but also the Middle East, and China.
“As many of these were pictures of documents, it appears that it was a deliberate leak done by someone that wished to damage the Ukraine, U.S., and NATO efforts,” Mick Mulroy, a former senior Pentagon official, was quoted saying.
Officials say the documents do appear to be authentic Defense Department documents, but they have been modified in some ways to show scenarios more beneficial to Russia, such as lower figures for the number of Russian troops killed and inflated numbers of Ukrainian war dead.
Some of the documents show the supposed locations of Ukrainian air-defense systems, the quantities of air-defense missiles, and sensitive information about U.S.-provided arms and supplies.
Most of the documents were created in February, according to the Journal.
In addition to revealing classified intelligence on Ukraine, they also reportedly contain reports on Israel’s Mossad and details on U.S. discussions with South Korea.
The documents appear to have gradually been leaked over the last few weeks. Many of them were posted in a Discord message board for Minecraft fans in early March, according to the Journal.
“If some guy on Minecraft Map Discord was able to find these and share them a few days after they first appeared on March 1, there is a pretty good chance that Russian intelligence was able to get a glance at them, too,” Aric Toler, head of research and training with Bellingcat, was quoted as saying.