Russia warns NATO it could use nuclear weapons over attempts to isolate Kaliningrad - Reuters

Moscow accused NATO of pursuing a “dangerous and reckless course” that carried “high risks of the outbreak of a direct armed conflict.”

The note also raised the possibility of Russian strikes against “decision-making centers” in NATO member states “right from the outset.”

“Russia will be ready to use the entire arsenal of forces and capabilities at its disposal, including nuclear weapons, in order to defend its territory should NATO countries undertake any attempt aimed at isolating the Kaliningrad Region from the rest of the country,” the document said.

Kaliningrad is a heavily militarized Russian exclave on the Baltic Sea, bordered by NATO members Poland and Lithuania. Reuters said Russia has recently expressed growing concern over NATO military exercises and other activities around the region.

NATO rejected Moscow's claims in a written response also seen by Reuters, saying none of the alliance's exercises or activities posed a threat to Russian territory.

“We urge the Russian Federation to refrain from increasingly reckless behaviour towards the Allies and to cease its irresponsible nuclear rhetoric,” NATO said. The alliance also called on Russia to end its full-scale invasion of Ukraine.

Russian embassies in at least three European countries have issued statements in recent days accusing NATO of escalating tensions through military exercises and scenarios involving Kaliningrad. Kremlin spokesperson Dmitry Peskov described the messages as reminders to “hotheads in Europe.”

A senior European defense official told Reuters it was the first time since the Cold War that Russia had threatened NATO in this manner, calling the development “serious.”