The documents began circulating on Friday on the Telegram app, and U.S. officials are looking for the original source of the leak.
The F.B.I. is investigating a leak of highly classified documents that appear to show Israel’s plans to retaliate against Iran for a missile attack earlier this month, the agency confirmed on Tuesday.
The documents were prepared by the National Geospatial-Intelligence Agency, which is responsible for analyzing images and information collected by American spy satellites. The N.G.A. is part of the United States intelligence community and conducts sensitive work in support of clandestine and military operations.
The information in the documents is highly classified and details interpretations of satellite imagery that shed light on a possible strike by Israel on Iran. They began circulating on Friday on the Telegram app. U.S. officials have previously said they did not know from where the documents had been taken, and that they were looking for the original source of the leak.
In a statement, the F.B.I. said it was “working closely with our partners in the Department of Defense and intelligence community. As this is an ongoing investigation, we have no further comment.” The bureau is responsible for investigating violations of the Espionage Act, which outlaws the unauthorized retention of defense-related information that could harm the United States or aid a foreign adversary.
Israel has made it clear it intends to retaliate for an Iranian missile barrage on Oct. 1. Iran’s Islamic Revolutionary Guards Corps said that the strike was launched after the assassinations of Hezbollah’s leader, Hassan Nasrallah, in Lebanon; Hamas’s political leader, Ismail Haniyeh, killed in Tehran in July; and an Iranian commander. U.S. officials believe the strike could take place in the coming days.
Adam Goldman writes about the F.B.I. and national security. He has been a journalist for more than two decades. More about Adam Goldman