On October 20, U.S. House Speaker Mike Johnson announced that the United States is investigating the leak of two highly classified intelligence documents that detail Israel’s preparations for potential retaliatory strikes against Iran.

When asked about the leak, Johnson stated, “The investigation is ongoing, and I’ll receive a briefing on the situation in a few hours.”

Further confirming the authenticity of the leak, Johnson called the incident “deeply concerning,” according to reports from CNN and The Guardian.

The leaked documents, both marked “TOP SECRET,” indicate access restricted to the United States and its Five Eyes allies—Australia, Canada, New Zealand, and the United Kingdom. Additional contents are designated for sharing exclusively between the U.S. and the U.K.

One document is titled, “Israel: Air Force Continues Preparations for Striking Iran and Will Conduct a Second Large-Scale Military Exercise.” The other is titled, “Israeli Defense Forces Continue Key Ammunition Preparations and Secret Drone Operations.” Both documents are dated October 16, and they were leaked the following day.

U.S. officials have indicated that the investigation focuses on how these classified documents were obtained, including whether they were intentionally leaked by U.S. intelligence personnel or acquired through other means. The inquiry will also explore the possibility of other intelligence being compromised.