Russia has issued one of its starkest warnings of the Ukraine war, with senior official Dmitry Medvedev declaring that Moscow could use nuclear weapons if it believes Western powers are drawing Kyiv into a nuclear confrontation.

Medvedev, Deputy Chairman of Russia’s Security Council and a close ally of President Vladimir Putin, made the threat in a statement on Telegram after Russia’s Foreign Intelligence Service alleged that the United Kingdom and France were preparing to transfer nuclear capabilities to Ukraine. Western governments have repeatedly denied any intention to arm Kyiv with nuclear weapons, but Moscow has used such claims to justify its escalating rhetoric.

Medvedev framed the alleged Western move as a direct transfer of nuclear weapons to a country already at war with Russia, insisting that this would “radically change” the nature of the conflict. He argued that such a step would cross what Moscow sees as a red line, transforming the war from a conventional confrontation into a nuclear one with global implications.

He warned that if Ukraine were to receive nuclear weapons or nuclear delivery systems, Russia would respond with what he called a symmetrical measure. That response, he suggested, could include the use of non-strategic, or tactical, nuclear weapons against targets in Ukraine that Russian authorities deem a threat to national security.

Medvedev also signaled that any country involved in supplying nuclear capabilities to Kyiv would be treated as a direct participant in a nuclear conflict with Russia. This language appears aimed at deterring NATO members from deepening military support for Ukraine, particularly in advanced missile systems and other technologies that Moscow portrays as nuclear-related.

The remarks fit a broader pattern in which Russian officials invoke nuclear threats to pressure Western governments and to signal that Moscow is prepared to escalate if it feels cornered. Analysts note that while Russia’s formal nuclear doctrine allows the use of such weapons if the state’s existence is threatened, repeated public references to nuclear options risk normalizing the idea of their use.

For Ukraine and its allies, Medvedev’s comments underscore the high-stakes nature of the conflict and the Kremlin’s willingness to leverage nuclear fears as it seeks to deter further Western involvement on the battlefield.