Live updates: Follow the latest on Israel-Gaza
The FBI on Tuesday said it is investigating the alleged leak of classified US intelligence documents describing Israel's preparations for a retaliatory strike on Iran.
Iran has been bracing for a response after it fired nearly 200 ballistic missiles at Israel on October 1 in retaliation for the killings of Tehran-backed senior figures in Hamas and Hezbollah leader Hassan Nasrallah.
The classified documents, circulated on the Telegram app last week by an account called Middle East Spectator, describe Israeli preparations for a possible strike – but do not identify any targets.
“The FBI is investigating the alleged leak of classified documents and working closely with our partners in the Department of Defence and intelligence community,” the agency said in a statement.
Pentagon press secretary Maj Gen Pat Ryder said a Defence Department official who had been identified on social media appears not to have been involved in the leak.
“This investigation is in its first few days, and it's important to let the investigation run its course,” Maj Gen Ryder told reporters. “To my knowledge, this official is not a subject of interest.”
White House national security spokesman John Kirby told reporters on Monday that US authorities were unaware if the documents had been leaked or hacked.
“We're not exactly sure how these documents found their way into the public domain,” Mr Kirby said, adding that such a leak would be “unacceptable”.
The documents were reportedly prepared by the National Geospatial-Intelligence Agency and detail US assessments of Israeli Air Force and Navy operations, based on satellite imagery from October 15 to 16.
US President Joe Biden had indicated last week that his administration knew about Israel's plans. Republican presidential candidate Donald Trump seized on the apparent leak on Tuesday, portraying it as an example of government incompetence.
“They leaked all the information about the way that Israel is going to fight, and how they're going to fight, and where they're going to go,” the former US president said, exaggerating the content of the classified material.