By Bond Robertson 
One expert says the leak could damage trust between the United States and Israel.
The United States launched an investigation after top-secret intelligence documents were leaked about Israel's plans to attack Iran CNN.
The attack comes in retaliation for the Iranian missile attack on October 1.
The documents, dated October 15 and 16, began circulating online on Friday after being posted on Telegram by an account called Middle East Spectator. It is classified as top secret and should only be shared with the United States and “Five Eyes” allies Australia, Canada, New Zealand and the United Kingdom.
– This is very disturbing, a US official tells CNN.
It can damage trust
One document, purportedly from the National Geospatial-Intelligence Agency, is supposed to show how Israel transports the munitions. The second document allegedly from National Security AgencyIt will showcase Israeli Air Force exercises including surface-to-air missiles.
According to CNN, the two documents will be linked to plans to attack Iran.
The leak comes at a very sensitive time in the relationship between the United States and Israel and could harm trust between the two countries.
The documents describe preparations that Israel appears to be making to launch an attack on Iran, in response to the Iranian missile attack on October 1. One document also refers to something Israel has never publicly confirmed: that the country possesses nuclear weapons.
– Serious breach
The document says the United States has seen no indication that Israel plans to use nuclear weapons against Iran.
– If it is true that Israel's tactical plans to respond to the Iranian attack on October 1 were leaked, then this is a dangerous leak, says Mick Mulroy, former Deputy Secretary of State for Defense in the Middle East.
Future cooperation between the United States and Israel could also face challenges. He says trust is an important part of this relationship, and depending on how the documents are leaked, that trust could be damaged as well.
It is currently unclear how the documents were published, whether they were hacked or intentionally leaked.
The United States is already on high alert for Iranian hacking campaigns. According to CNN, the leak could lead to further tensions in the relationship between the United States and Israel. An American official says, “These two documents are bad, but not terrible.” “The concern is whether there are more.”