US officials said the investigation is in its early stages and those running it have not ruled out the possibility that pro-Russian elements were behind the leak, which is considered one of the most serious security breaches since more than 700,000 documents, videos and diplomatic cables appeared on the WikiLeaks website in 2013.
The Russian embassy in Washington and the Kremlin did not respond to requests for comment.
Following the disclosure of the leak, Reuters has reviewed more than 50 documents labeled “Secret” and “Top Secret” that first appeared last month on social media websites, starting with Discord and 4Chan. Although some of the documents were released weeks ago, the New York Times first reported their existence on Friday.
Reuters has not independently verified the authenticity of the documents. Some gave estimates of casualties on the Ukrainian battlefield that appeared to have been doctored to minimize Russian losses.
It’s unclear why at least one is marked unclassified but includes top-secret information. Some documents are marked “NOFORN”, which means that they cannot be issued to foreign citizens.
Two US officials told Reuters on Sunday that they have not ruled out that the documents may have been manipulated to mislead investigators as to their origin or to spread false information that could harm US security interests.
One of the documents, dated February 23 and marked “Secret,” describes in detail how Ukraine’s S-300 air defense systems would be depleted by May 2 at the current rate of use.
Such well-guarded information could be of great use to Russian forces, and Ukraine said its president and senior security officials met on Friday to discuss ways to prevent leaks.
Watching the allies
Another document, marked “Top Secret” and from a March 1 CIA Intelligence update, claims that the Mossad intelligence agency was encouraging protests against Israeli Prime Minister Benjamin Netanyahu’s plans to tighten controls over the Corta. Supreme.
The document says that the United States learned of this through signals intelligence, suggesting that the United States had been spying on one of its most important allies in the Middle East.
In a statement on Sunday, Netanyahu’s office described the claim as “lying and unsubstantiated.”
Another document detailed internal discussions among high-ranking South Korean officials about US pressure on Seoul to help supply weapons to Ukraine, and its policy of not doing so.
A South Korean presidential official said on Sunday the country was aware of the news about the leaked documents and planned to discuss “the issues raised” with Washington.
The Pentagon has not commented on the contents of any specific documents, including the apparent allied surveillance.
Two US officials, speaking on condition of anonymity, said that while the leak worried the Pentagon and intelligence agencies, the documents showed a snapshot from more than a month ago and not more recent assessments.
The two officials said the military and intelligence agencies were reviewing their processes to determine the extent to which some intelligence information is shared internally.
The Pentagon reiterated Sunday that it was reviewing the matter and had submitted a formal request to the Justice Department to investigate the incident.
The Justice Department said Friday it was in contact with the Defense Department and launched an investigation into the leak. He declined to comment further.
Those responsible are studying what motivations a US official or group of officials would have for leaking such sensitive information, said one of the sources who spoke to Reuters.
The official said investigators were considering four or five theories, ranging from a disgruntled employee to an insider threat actively seeking to undermine US national security interests.