UPDATE/COMMENT: Ive been getting a lot of questions about this remarkable claim by Kyiv, specifically: Wheres the hard evidence? I find this story to be plausible, given known Russian intelligence tradecraft, what they call konspiratsiya, but the evidence weve seen to date isnt exactly rock solid (I wont say a slam dunk, thank you very much). The SBU has set a high bar for itself with its aggressive, and highly successful, public outreach in recent months, including its own YouTube channel where it has posted a lot of nearly raw intelligence, mainly SIGINT (see the next story). That Kyiv has not done so here tells me one of three things is going on:
1. The SBU has access to high-level Kremlin SIGINT, meaning they have cracked top-grade Russian codes, and releasing that SIGINT would compromise a very valuable source that Kyiv very much needs right now.
2. The SBU has a high-placed HUMINT asset in the Kremlin camp and compromising that source by releasing too much information here would be stupid as war with Russia looms.
3. This is an analytically-derived conclusion, based on a lot of evidence from many sources, none of them conclusive alone but which, taken together, lead to a firm conclusion based on multi-INT analysis.