WASHINGTON (AP) The United States is investigating an unauthorized release of classified documents that assess Israels plans to attack Iran , three U.S. officials told The Associated Press. A fourth U.S. official said the documents appear to be legitimate.

The documents are attributed to the U.S. Geospatial Intelligence Agency and National Security Agency, and note that Israel was still moving military assets in place to conduct a military strike in response to Irans blistering ballistic missile attack on Oct. 1. They were sharable within the Five Eyes, which are the U.S., Great Britain, Canada, New Zealand and Australia.

The documents, which are marked top secret, were posted to the Telegram messaging app and first reported by CNN and Axios. The officials spoke on the condition of anonymity because they were not authorized to discuss the matter publicly.

The investigation is also examining how the documents were obtained including whether it was an intentional leak by a member of the U.S. intelligence community or obtained by another method, like a hack and whether any other intelligence information was compromised, one of the officials said. As part of that investigation, officials are working to determine who had access to the documents before they were posted, the official said.