Elon Musk responded to accusations allegedly made against him by Dmitry Rogozin, the head of Russia’s space agency, Roscosmos, by suggesting that he might die “under mysterious circumstances” in a cryptic tweet that he posted on Sunday night.

“If I die under mysterious circumstances, it’s been nice knowin ya,” the Tesla CEO wrote shortly after sharing a message from Rogozin who accused Musk of being  “involved in supplying the fascist forces in Ukraine with military communication equipment” adding that “for this, Elon, you will be held accountable like an adult – no matter how much you’ll play the fool.”

Rogozin repeated rhetoric that falsely claims that Russia’s invasion of Ukraine is related to “denazifying” their neighboring country. In his alleged comments, the Russian official claims that Starlink, a company run by Musk, delivered equipment to Ukrain and was assisted by the Pentagon.

Indeed, Musk tweeted in February that “Starlink service is now active in Ukraine. More Terminals en route.” The Washington Post reports that the U.S. federal government paid millions of dollars for a significant portion of the equipment and transportation costs.

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Rogozin also said that Musk would be “held accountable like an adult” for the alleged actions. The Starlink and Tesla executive responded by saying that “the word Nazi doesn’t mean what he seems to think it does.”

Scholars claim that Russia’s government has attempted to push a “denazification” argument in order to invoke the second world war, a historical point of pride for the nation. Several experts told NPR in March, though, that the strategy is a “harmful distortion and dilution of history” that is part of a long-running attempt to delegitimize Ukraine.

The message was an apparent reference to the reports of assassinations carried out by the Russian state. For example, the BBC recently reported that a Russian agent tied to a secret assassination squad followed Boris Nemstov, a rival of President Vladimir Putin, on 13 occasions before he was eventually murdered in 2015, just steps from the Kremlin. He was killed only days before he was due to lead a protest against Russia‘s annexation of the Crimean peninsula.