The FBI and Pentagon have launched an investigation into the leak of classified U.S. intelligence regarding Israel’s potential plans for a retaliatory strike on Iran.

In a statement on Tuesday, the FBI confirmed: "The FBI is investigating the alleged leak of classified documents and is working closely with the Department of Defense and Intelligence Community. As this is an ongoing investigation, we have no further comment."

According to reports, the leaked documents include satellite imagery analysis from the U.S. National Geospatial-Intelligence Agency and the National Security Agency. The documents reportedly outline Israeli preparations for a retaliatory strike following Iran's missile barrage on Israel on October 1 but do not specify any actual targets.

The documents were circulated last week on the Telegram app by an account named Middle East Spectator.

White House national security spokesman John Kirby told reporters on Monday that U.S. authorities are still uncertain whether the exposure was due to a leak or a hack.

"We're not exactly sure how these documents found their way into the public domain," Kirby said. "The Department of Defense is investigating, and they will try to determine how this occurred."

Kirby emphasized that President Joe Biden is "deeply concerned about any leakage of classified information into the public domain," calling such incidents unacceptable.