The United States launched an investigation into the leak of highly classified intelligence detailing Israel’s preparations for a potential retaliation against Iran, according to three sources familiar with the matter. One of the sources confirmed the authenticity of the documents, as per a CNN report.

A US official described the leak as “deeply concerning” in a statement to CNN.

The documents, dated October 15 and 16, appeared online on Friday through the Telegram channel “Middle East Spectator.” Marked as “top secret,” the documents were intended for access only by the US and its “Five Eyes” intelligence-sharing allies: Australia, Canada, New Zealand, and the United Kingdom, as per the report.

Israel’s preparations for strike on Iran

The leaked documents reportedly detailed Israel’s planning for a strike against Iran, including the movement of munitions. One document, attributed to the National Geospatial-Intelligence Agency, outlined these military preparations.

Another document, which cited the National Security Agency, described Israeli air force exercises involving air-to-surface missiles, believed to be part of Israel’s preparations for an attack on Iran, as per CNN report.

Investigation launched

The US government opened an investigation to determine who had accessed the classified documents. A US official confirmed that such a leak automatically triggered involvement from the FBI, along with the Pentagon and intelligence agencies. The FBI declined to comment on the situation.

This breach of sensitive intelligence occurred at a delicate time for US-Israeli relations. Israel reportedly prepared to strike Iran in response to a missile barrage from Tehran on October 1. One of the leaked documents also alluded to Israel’s possession of nuclear weapons — something the country has neither confirmed nor denied publicly. However, it stated that the US had not observed any indications of Israel planning to use nuclear weapons in the conflict with Iran.

“If it was true that Israeli tactical plans to respond to Iran’s attack on October 1 were leaked, it was a serious breach,” said Mick Mulroy, a former deputy assistant secretary of defense for the Middle East and a retired CIA officer, as quoted by CNN.

Mulroy further emphasized that the leak could have impacted US-Israeli relations, noting, “The future coordination between the US and Israel could have been challenged as well. Trust is a key component in the relationship, and depending on how this was leaked, that trust could have eroded,” as quoted by CNN.

The National Security Council referred CNN to the Office of the Director of National Intelligence and the Pentagon for further comment. Both the Pentagon and the National Geospatial-Intelligence Agency declined to respond, as per CNN report.

A US official described the situation, stating, “These two documents were bad, but not horrible. The concern was if there were more,” as quoted by CNN.

It remained unclear whether the documents were hacked or deliberately leaked. The US had already heightened its alert regarding Iranian cyber operations, especially after intelligence agencies reported in August that Iran had infiltrated documents belonging to Donald Trump’s campaign, as per the report.

This latest leak followed other high-profile breaches of US intelligence. In 2023, a 21-year-old Air National Guardsman compromised sensitive information by posting it on the social media platform Discord. That leak strained US relations with several allies, including South Korea and Ukraine, as per CNN report.