WASHINGTON (AP) — President Joe Biden is "deeply concerned" about the unauthorized release of classified documents on Israel's preparation for a potential retaliatory attack on Iran, a White House spokesman said Monday.
The Biden administration is still not certain if the classified information was leaked or hacked, White House national security spokesman John Kirby said. Officials don't have any indication at this point of "additional documents like this finding their way into the public domain," he said.
Kirby added that the Pentagon is investigating. U.S. officials on Saturday had confirmed an investigation by the administration.
"We're deeply concerned, and the president remains deeply concerned about any leakage of classified information into the public domain. That is not supposed to happen, and it's unacceptable when it does," Kirby said.
The documents are attributed to the National Geospatial-Intelligence Agency and National Security Agency, and note that Israel was still moving military assets in place to conduct a military strike in response to Iran's blistering ballistic missile attack on Oct. 1. They were sharable within the "Five Eyes," an intelligence alliance comprised of the U.S., Great Britain, Canada, New Zealand and Australia.
Marked top secret, the documents first appeared online Friday on the Telegram messaging app and quickly spread among Telegram channels popular with Iranians.
Analysts at the SITE Intelligence Group, a consultancy that monitors and analyzes online threats from extremist groups, tracked the release of the documents to a Telegram channel popular with Iran-backed militias. The channel contained posts from an anonymous user with a long history of posting other supposedly top-secret content who said they had access to the documents. The user also wrote that they had sold some of the material and provided it to the Iranian military.
The Telegram channel identifies itself as being based in Tehran, Iran's capital. It previously published memes featuring Iran's Supreme Leader Ayatollah Ali Khamenei and material in support of Tehran's self-described "Axis of Resistance," which includes Middle East militant groups armed by the Islamic Republic.
One of the two documents resembled the style of other material from the National Geospatial-Intelligence Agency leaked by Jack Teixeira, an Air National Guardsman who pleaded guilty in March to leaking highly classified military documents about Russia's war on Ukraine and other national security secrets.
The release comes at a pivotal time in the Middle East, as Israel considers its response to Iran's attack.
The U.S. has urged Israel to take advantage of its elimination of Hamas leader Yahya Sinwar and press for a cease-fire in Gaza and has likewise urgently cautioned Israel not to further expand military operations in the north in Lebanon and risk a wider regional war.
However, Israel's leadership has repeatedly stressed it will not let Iran's missile attack go unanswered.
The investigation into the release of the documents may take some time as authorities look for digital or physical clues that could reveal how the information got out, and what implications it may have for information management and intelligence sharing with U.S. allies, according to Gavin Wilde, a senior fellow in the Technology and International Affairs Program at the Carnegie Endowment for International Peace.
"I imagine they'll eventually get to the bottom of it," said Wilde, who formerly worked on the National Security Council. "The intelligence community has gotten a lot better at digital chain of custody — who has seen a particular document, how many times it's been shared, and with whom."
White House Press Secretary Karine Jean-Pierre on Monday declined to comment on what changes the government has made to better safeguard top secret information in the aftermath of the Discord leak. She added that Biden has "complete confidence" in the Pentagon, Justice Department and intelligence community following the latest unauthorized disclosure.
The nation's spy agencies have worked to bolster cybersecurity since the Discord leak and the conviction of former NSA contractor Reality Winner. Accounting for human behavior, however, can be a harder challenge, according to Shawnee Delaney, a former officer at the Defense Intelligence Agency who is now CEO of the Vaillance Group, a private threat analysis firm.
"Cybersecurity isn't just a technological issue," Delaney told The Associated Press. "It's a human one, and humans are wholly unpredictable."
Spokespeople for the Pentagon and the NSA said officials were aware of the incident but had no further comment.