WASHINGTON (NewsNation) — The Department of Justice and the Pentagon continue to investigate and assess the impact of a major leak of classified U.S. documents that’s shaken Washington.

While the White House, Department of Defense and DOJ have not said much about the leaked classified information on Tuesday, the question remained of how these U.S. secrets got leaked onto social media.

The spokesperson for the National Security Council said he’s not sure if more leaks are coming.

“We don’t know who’s responsible for this and we don’t know if they have more that they intend to post. So we’re watching this and monitoring it as best we can, but the truth in the honest answer to your question is we don’t know. And is that a matter of concern to us? You’re darn right it is,” National Security Council spokesman John Kirby said during a White House press briefing Monday.

President Joe Biden was briefed on the leak late last week, but the White House and the Pentagon have yet to confirm whether the documents are real.

The leaked documents reportedly involve maps and satellite images from February and March exposing that Ukraine had a shortage of air munitions as well as intelligence on key U.S. allies Israel and South Korea.

“These photos appear to show documents similar in format to those used to provide daily updates to our senior leaders on Ukraine and Russia-related operations, as well as other intelligence updates,” Chris Meagher, top spokesman for the Pentagon, said.

The leak has reportedly caused Ukrainian President Volodymyr Zelenskyy to adjust his military plans accordingly, CNN reported.

The Washington Post reported that the leaked documents also revealed that Egypt had secretly been preparing to send about 40,000 rockets to Russia. Egyptian President El-Sisi reportedly instructed officials to keep it quiet to “avoid problems with the West.”

Meagher did not say how many intelligence officials would have had access to the documents and would not confirm whether there are roughly 100 pages, as reported.

The source of the leaks is not yet clear. The scale of the exposure has also yet to be determined. Also unclear is whether any government worked to share the documents or manipulate them.

Reuters reported that three unnamed U.S. officials said Russia or pro-Russian elements are likely behind at least the first batch of leaks.

But the breach underscores the difficulties the U.S. and other governments face in securing classified information. Congressional reviews and experts have long warned of weaknesses in U.S. counterintelligence, of the challenges of monitoring an estimated 3 million people with security clearances, and of agencies producing and over-classifying so much information that the U.S. cannot reliably control it.

The Associated Press and The Hill contributed to this report.