In a diplomatic document sent to NATO and seen by Reuters, Moscow accused the alliance of pursuing a “dangerous and reckless course” carrying “high risks of the outbreak of a direct armed conflict”. The document also warned of the possibility of Russian strikes against decision-making centres in NATO member states from the beginning of any conflict.
“Russia will be ready to use the entire arsenal of forces and capabilities at its disposal, including nuclear weapons,” the Russian note said, if NATO countries attempted to isolate Kaliningrad from the rest of Russia.
Kaliningrad is a heavily militarised Russian exclave situated between NATO members Poland and Lithuania and bordering the Baltic Sea. Its position makes it strategically important to Moscow while also leaving it potentially vulnerable because it is separated from mainland Russia by NATO territory.
NATO rejected the warning and said the alliance’s military activities posed no threat to Russia. Secretary-General Mark Rutte said NATO was a defensive alliance and called on Moscow to stop its nuclear threats.
“We are a defensive alliance. And stop the nuclear threats. This is absolutely not called for and not helpful,” Rutte said. He also said there was no immediate threat to NATO territory from Russia and indicated that the alliance did not regard Moscow’s warning as changing its assessment of the security situation.
In its written response to Moscow, NATO said none of its exercises or activities posed a threat to Russian territory. The alliance urged Russia to end its full-scale invasion of Ukraine and to refrain from what it called increasingly reckless behaviour and irresponsible nuclear rhetoric.
The Russian warning comes amid a broader rise in military tensions in the Baltic region since Russia’s full-scale invasion of Ukraine in 2022. NATO has strengthened its eastern flank, while Finland and Sweden have joined the alliance, increasing the number of NATO members around the Baltic Sea. Moscow has increasingly portrayed NATO military activity in the region as a threat to Kaliningrad.
Russia has also accused NATO of preparing an air and naval blockade of Kaliningrad. Russian diplomatic missions in several European countries have issued similar warnings, accusing NATO of escalating tensions through military exercises and scenarios involving the enclave. NATO has rejected those claims and said its activities are defensive.
The exchange has raised concern about the possibility of miscalculation. Security analysts have identified Kaliningrad as a potential flashpoint because of its geographical position and the military capabilities stationed there. Reuters reported that the territory provides Russia with a platform for air defence, missile and naval forces capable of projecting power into northern and central Europe, while its separation from the rest of Russia could make it difficult to reinforce during a conflict.
Kremlin spokesman Dmitry Peskov defended Moscow’s warnings as a way of reminding what he described as European “hotheads” of Russia’s nuclear doctrine. NATO, meanwhile, has said it will continue supporting Ukraine and strengthening its defences.
The latest exchange leaves Kaliningrad at the centre of a widening confrontation in the Baltic, where military deployments, competing threat assessments and nuclear rhetoric have increased the risks surrounding any future crisis.
