Evidence

I attempted multiple web searches to verify this claim but was blocked by a tool-call limit for this turn and could not retrieve any search results. From general background knowledge, there was a real and widely reported episode in mid-2022 in which Russian officials (including Dmitry Medvedev and Kremlin spokesman Dmitry Peskov) made statements about Kaliningrad after Lithuania restricted rail transit of certain EU-sanctioned goods, with some Russian commentary invoking the region's military/nuclear-capable missile deployments. However, I found no independent reporting I could confirm in this session specifically attributing a formal diplomatic note or nuclear threat statement to 'Russia's embassy in Ireland,' nor any Reuters article I could verify that cites such a note. Without being able to run searches, I cannot confirm Reuters, AFP Fact Check, Bellingcat, or EUvsDisinfo have examined this specific claim.