Leaked documents show US intelligence information about Israel’s plans to attack Iran, sources say

(CNN) — The U.S. is investigating the leak of top-secret U.S. intelligence on Israel’s retaliatory plans against Iran, according to three people familiar with the matter. One of the acquaintances confirmed the authenticity of the documents.

The leak is “deeply concerning,” a US official told CNN.

The documents, dated Oct. 15 and 16, began circulating online Friday after they were posted on Telegram by an account called “Middle East Spectator.”

They are marked top secret and indicate that they are only visible to the US and its “Five Eyes” allies – Australia, Canada, New Zealand and the UK.

They describe the preparations that Israel is apparently making for an attack on Iran. One of the documents, purportedly compiled by the National Geospatial-Intelligence Agency, states that the plans involve Israel transporting munitions.

Another document says it comes from the National Security Agency and describes Israeli Air Force exercises with air-to-surface missiles, which are also believed to have served as preparation for an attack on Iran. CNN does not quote or show the documents directly.

A US official said the investigation was looking into who had access to the alleged Pentagon document. Such a leak would automatically trigger an investigation by the FBI along with the Pentagon and US intelligence agencies. The FBI declined to comment.

The leak comes at an extremely sensitive time in US-Israeli relations and is likely to anger the Israelis, who have been preparing to attack Iran in response to Iran’s rocket fire on October 1.

“If it is true that Israeli tactical plans to respond to the Iranian attack on October 1 were leaked, that is a serious violation,” said Mick Mulroy, former deputy assistant secretary of defense for the Middle East and a retired CIA officer.

Mulroy added that “future coordination between the US and Israel could also be called into question. “Trust is a key component in the relationship, and depending on how this transpires, that trust could be undermined.”

The National Security Council referred CNN to the Office of the Director of National Intelligence and the Pentagon for comment. The Pentagon and the National Geospatial-Intelligence Agency declined to comment. CNN has reached out to the National Security Agency for comment.

Another US official said: “These two documents are bad, but not terrible. The concern is whether there are more.”

It is not clear how the documents became public and whether they were hacked or intentionally leaked. The US is already on high alert for Iranian hacking campaigns – US intelligence agencies said in August that Iran had hacked documents belonging to Donald Trump’s campaign.

Axios first reported on the leaked documents on Saturday.

A major U.S. intelligence leak last year also strained U.S. relations with allies and partners, including South Korea and Ukraine, after a 21-year-old Air National Guardsman posted top-secret information on the social media platform Discord.