WILLIAM BRANGHAM: Good evening, I'm William Brangham.

John Yang is away.

More details are emerging about how an apparent trove of intelligence documents leaked onto social media sites over the last few months.

With the Justice Department investigation already underway, the Washington Post is reporting that these files many seemingly from the Pentagon and highly classified provide details about the war in Ukraine, and how the U.S. allegedly spies on its allies and its foes.

It includes details about the near downing of a British spy plane by Russia, near Ukraine last year.

For the latest on this, we are joined now by Dan Lamothe.

He covers the Pentagon and the U.S. military for The Washington Post and has been reporting the story.

Dan, thanks so much for being here.

Before we get into the content of what these documents say, is there any question as to whether or not these are legitimate intelligence and military documents?

DAN LAMOTHE, The Washington Post: There's no question that there are some legitimate military and intelligence documents that have been posted online.

The problem has become as we toured through these, some of these, as they have kind of proliferated across the internet have been doctored.

So you're sort of trying to sort through what's a real document?

What's a real document that's been altered?

And whether there might be any fakes in here outright?

WILLIAM BRANGHAM: So I touched briefly on some of the things that they reveal, but how would you sort of describe what is the bulk of what's in these documents?

DAN LAMOTHE: The majority of the documents that I have seen appear to be from probably the same packet of information, many of them are stamped with joint staff.

So this would be the Chairman of the Joint Chiefs of Staff.

One of the reasons these documents do spread is because there's a lot of helpful information for staying up to date on current operations.

That's OK, so long as it stays within the world of people who has have the clearance to see them.

WILLIAM BRANGHAM: As I mentioned, there's details in here about how the Ukrainian military is holding up against the Russian invasion, how the Russians themselves are doing.

But there are also details in there about how the U.S. spies on some of its allies and its foes.

In particular, what do they reveal in that regard?

DAN LAMOTHE: Yes, I mean, there's a number of troubling things in terms of it being out in the open and then even as he sort through how to report this, there's the -- there's at least a discussion to be have when do you actually put this into a newspaper or a television broadcast, but we've reached a point where these things have proliferated through Telegram, Twitter, Discord is where the documents seem to have been first uploaded.

So, and then they've also been online for weeks.

So they have spread a great deal.

So then you -- at some point, you need to have an honest conversation out in the open about what these things are, and what kind of problem it presents to having there.

In this case, the you know, the topics range from Iran to North Korea, Hungary, a number of different countries, it references satellite programs, it references signals intelligence.

So basically radio in their intercepts, in many ways, things that you don't necessarily want the sources and methods in terms of how this information has been gathered out in the open.

WILLIAM BRANGHAM: Can you give us a sense from talking to all of your sources, how big a deal they see this as, I mean, we've had leaks in the past, or WikiLeaks and the Pentagon papers in the Afghan papers.

Some of those were retrospective looks, but this is about ongoing current conflicts and crises all over the world, how troubled are administration and military officials about these leaks.

DAN LAMOTHE: And to my knowledge, at least, I don't think it's in the same bucket as a WikiLeaks leak or the Edward Snowden or something like that.

But it is nonetheless troubling to have some of the stuff in the open, particularly open assessments of Ukraine's combat capabilities, gaps in their capabilities.

You know, and the idea that these have been out and available for weeks, and in some cases, doctored, the doctoring often favorite Russian points of view.

So you start wondering, who has viewed them, how they may have shaped their operations around it?

And you know, there's a number of troubling consequences that could go with that.

WILLIAM BRANGHAM: As I mentioned, the Department of Justice is investigating this leak, what do we know about who might have stolen these and leak them out?

DAN LAMOTHE: Very little in terms of the initial source at this point.

I mean, the assumption would be the initial source would have had the clearance.

But there's also the possibility that the initial source was negligent with the documents as opposed to deliberately putting them online.

And they somehow ended up in somebody else's hands.

You know, in terms of the way this might look, anything that's printed out, and the documents that have been uploaded, at least the ones I've seen are basically photographs of printed pages.

So, you know, the assumption would be that the U.S. government's that can then go back and look to try and figure out who had printed copies, who may have printed it out that maybe shouldn't have, and kind of tried to backtrack, who would the universe people is that have these printed copies in their hands back in February and March.

WILLIAM BRANGHAM: You touched on this a little bit before.

But what is the possibility?

How concerned are your sources that that the leak of these documents could hurt U.S. interest in the sense that we either are revealing how we gather intelligence or it gives other adversaries the opportunity then to combat that surveillance?

DAN LAMOTHE: In terms of the specifics, they've been very careful about talking to -- talking about that, and the steps they might take other than acknowledging that they are trying to take a step -- take steps to kind of combat that and deal with that.

The other thing is they're going to have to probably have hard conversations with allies and partners.

You know, when you're referencing the spine you do on a longtime ally, or, you know, basically there's some acknowledgement here that we're very tracking, closely tracking both Russia and Ukraine, both in terms of what they're doing, but also what they're saying and how they're thinking to the extent we can, you know, like, those are difficult conversations to have with somebody even if you're partnered.

WILLIAM BRANGHAM: Dan Lamothe of the Washington Post.

Thank you so much for being here.