The U.S. is investigating the leak of highly classified American intelligence about Israel's plans to retaliate against Iran for its missile attack earlier this month.
A pair of documents posted online detail recent moves at several Israeli air force bases, including the transfer of advanced munitions, and a large military exercise conducted last week, Axios reported Saturday.
The documents are authentic, a person familiar with the matter told CNN, and a U.S. official told the network that the leak was "deeply concerning."
The intelligence was prepared by the National Geospatial-Intelligence Agency and provides analysis of images captured by American spy satellites, according to the New York Times.
The documents, marked top secret and dated Tuesday and Wednesday, began circulating Friday after being posted on the online Telegram messaging app, CNN said.
Markings on them reportedly indicate they were only meant to be seen by officials in the "Five Eyes" alliance of the U.S., U.K., Canada, Australia and New Zealand.
Multiple U.S. officials reportedly said an investigation into the leak was underway.
One official told CNN that "these two documents are bad, but not horrible. The concern is if there are more."
The documents were posted on a Telegram channel named "Middle East Spectator" that AP said identifies itself as being based in Tehran, Iran's capital, and which has posted material in support of Iran's self-described "Axis of Resistance" against Israel and the U.S.
In statements posted on the channel, Middle East Spectator described itself as an "open-source news aggregator" composed of independent journalists "not tied to any government entity or organization."
It also said that the documents came from an anonymous source on Telegram who shared them with "various other people and news outlets" and that it was "not aware of any additional leaked classified U.S. documents."
The leak followed the online posting of other classified material from the National Geospatial-Intelligence Agency by then-Air National Guardsman Jack Teixeira, who shared a huge trove of stolen documents on the Discord app in 2022 and 2023.
Teixeira pleaded guilty in March to six counts of willful retention and transmission of classified information relating to the national defense and is awaiting sentencing next month.
He also faces a military court martial on charges of disobeying orders and obstructing justice.
