https://www.bbc.com/news/world-europe-65225985Ukraine war: Who leaked top secret US documents - and why?
What to make of the dozens of classified American Defence Department documents - maps, charts and photographs - now circulating on the internet?
Complete with timelines and dozens of impenetrable military acronyms, the documents, some of them marked "top secret", paint a detailed picture of the war in Ukraine.
They tell of the casualties suffered on both sides, the military vulnerabilities of each and, crucially, what their relative strengths are likely to be when Ukraine decides to launch its much-anticipated spring offensive.
How real are these printed pages, unfolded and photographed, possibly on someone's dining room table? And what do they tell us, or the Kremlin, that we did not already know?
First things first: this is the biggest leak of secret American information on the war in Ukraine since Russia's full-scale invasion 14 months ago. Some of the documents are as much as six weeks old, but the implications are huge.
Pentagon officials are quoted as saying the documents are real.
Take casualty figures. It comes as little surprise to learn that the US estimates that between 189,500 and 223,000 Russian soldiers have been killed or wounded.
The equivalent figure for Ukraine's losses - between 124,500 and 131,000 - is also in line with ballpark figures briefed to journalists in recent weeks.
In both cases, the Pentagon says it has "low confidence" in the figures, due to gaps in information, operational security and deliberate attempts, probably by both sides, to mislead.
Tellingly, this is the one place where attempts have been made to alter the documents to make it look as if Ukraine is experiencing the worst casualties.
A version which appeared on a pro-Russian Telegram site took the number of Ukrainian "killed in action" ("16k-17.5k") and put those on the Russian ledger, while flipping the numbers on the Ukrainian side so they read "61k - 71.5k".All of which brings us to the question of who leaked the documents, and why?