What Do Leaked U.S. Intelligence Reports Say? Here Is a Quick Guide.

Leak or hack? Information or disinformation? A coup for Russia or a ploy by the United States?

Days after U.S. intelligence documents, some marked “top secret,” were found circulating on social media, questions remain about how dozens of pages from Pentagon briefings became public and how much stock to put in them.

Here is what we know about the documents.

Are the documents real?

Yes, officials say — at least, for the most part.

U.S. officials are alarmed at the exposure of secret information, and the Federal Bureau of Investigation is working to determine the source of the leak.

Some of the documents appear to have been altered, officials say. It is unclear who doctored the reports or why they did so. Whatever the reason, some of the material, military analysts, say, overstates American estimates of Ukrainian war dead and understates how many Russian troops have been killed since Moscow’s invasion of its neighbor last year.

Where did the materials come from?

The evidence that this is a leak, and not a hack, appears strong.

The material may be popping up Whac-a-Mole style on platforms like Twitter, 4chan and the Telegram messaging app — to say nothing of a Discord channel dedicated to the video game Minecraft — but what is being circulated are photographs of printed briefing reports.

That may not seem like much to go on, especially given the thousands of people said to have access to the material. But in 2017, a crease mark visible in the image of leaked National Security Agency material was enough to put investigators on the trail of a young Air Force linguist named Reality Winner.

The new documents may offer still more clues.

Online, they look like hastily taken photographs of pieces of paper sitting atop what appears to be a hunting magazine. Former officials who have reviewed the material say it appears that a classified briefing was folded up, placed in a pocket and then taken out of a secure area to be photographed.

Some documents were specifically marked for U.S. eyes only, increasing the likelihood that an American official leaked the information.

What did we learn about the war in Ukraine?

Though the documents may not fundamentally alter the understanding of what is happening on the battlefield, they may offer insights — or at least tantalizing clues — to the trained eye of a Russian war planner.

The documents do not contain specific battle plans, including about the Ukrainian counteroffensive expected in the next month so. But they detail secret American and NATO plans for building up the Ukrainian military ahead of that offensive.

They also suggest that the Ukrainian forces are in more dire straits than their government has acknowledged publicly, pointing specifically air-defense shortages and to the pace with which they are going through the American-supplied high-mobility artillery rocket system known as HIMARS.

And the mere fact that the materials leaked — and in particular the confirmation they offered that the U.S. government spies on allies and adversaries alike — may prove damaging to the generally unified coalition that has emerged to help Ukraine fend off the Russian invasion.

On the battlefield, however, some Ukrainian soldiers seemed inclined to chalk it up as just war in another form.

Has the U.S. penetrated Russian intelligence?

The leaked Pentagon documents reveals how deeply the United States has burrowed into Russia’s security and intelligence services, allowing Washington to warn Ukraine about planned strikes and gain insights into the strength of Moscow’s war machine.

The material reinforces an idea that intelligence officials have long acknowledged: The United States has a clearer understanding of Russian military operations than it does of Ukrainian planning.

The military apparatus is so deeply compromised, the documents suggest, that American intelligence has been able to obtain daily real-time warnings on the timing of Moscow’s strikes and even its specific targets.

That may now change.

The leak has the potential to do real damage to Ukraine’s war effort by exposing which Russian agencies the United States knows the most about, giving Moscow a potential opportunity to cut off the sources of information.

Disinformation? If so, whose?

Officials in Washington have described the documents’ release as a major intelligence breach, but in Kyiv and Moscow, there is agreement on two things: The information is suspect, and the goal is subterfuge. They just don’t agree on who is behind it.

In a statement to The New York Times, Mykhailo Podolyak, an adviser to Ukraine’s president, Volodymyr Zelensky, said the documents were filled with “fictional information.”

“There is not the smallest doubt that this is yet another element of hybrid warfare,” he said. “Russia is trying to influence Ukrainian society, sow fear, panic, mistrust and doubt. It’s typical behavior.”

The goal, the Ukrainians say, is to undercut the coming counteroffensive.

In Russia, pro-war military bloggers also pointed to the Ukrainian counteroffensive — but drew a different conclusion.

A post on Grey Zone, a Telegram channel associated with the Wagner militia, said: “We should not exclude the high probability that such a leak of classified information at the exact moment of the intensification of hostilities, and after the fact of the accomplished events displayed in the documents, is disinformation of Western intelligence in order to mislead our command to identify the enemy’s strategy in the upcoming counteroffensive.”

In other Russian Telegram channels, prominent voices say the original documents showed higher Russian losses, part of a “Western influence” operation intended to “ to instill poor morale in Russia and Russian forces,” according to the head of a British firm that tracks disinformation.

What other countries are named?

The leak appears to go well beyond classified material on Ukraine. Security analysts who have reviewed the documents on social media sites say the growing trove also includes sensitive briefing material on Canada, China, Israel and South Korea, in addition to the Indo-Pacific military theater and the Middle East.

Among the disclosures:

• A hacking group under the guidance of Russia’s Federal Security Service may have compromised a Canadian gas pipeline company in February and caused damage to its infrastructure.

• A Pentagon assessment concluded that the leadership of the Mossad, Israel’s foreign intelligence service, had encouraged the agency’s staff and Israeli citizens to participate in the antigovernment protests that roiled the country in March. Israel officials disputed the report.

• Officials in South Korea, a key American ally, torn between Washington pressure to help supply ammunition to Ukraine and its official policy of not providing lethal weapons to countries at war, feared that the United States might divert South Korean arms to Kyiv.

• The Russian military may be flailing, but the private Wagner mercenary group — led by an ally of President Vladimir V. Putin of Russia — is flourishing in much of the world, the documents say. Wagner is working to thwart American interests in Africa and has explored branching out to Haiti, right under the nose of the United States, the documents say, with an offer to help that country’s embattled government take on gangs.

Reporting was contributed by Helene Cooper, Eric Schmitt, Julian E. Barnes, Thomas Gibbons-Neff, Michael Schwirtz and Ivan Nechepurenko.