Russia threatened to use nuclear weapons against Nato countries if the alliance hinders access to Kaliningrad. Moscow sent a document to Nato this week warning of direct conflict. Nato responded by calling the move irresponsible nuclear rhetoric. The alliance said it remains ready to defend every inch of its territory.
Russia has threatened to use nuclear weapons against Nato countries if the western military alliance were to hinder access to its Baltic Sea exclave of Kaliningrad.
In a document sent to Nato this week, Moscow accused the alliance of taking a "dangerous and reckless course" towards Russia and its exclave, according to two officials familiar with the matter. The officials said it included a warning about "high risks of the outbreak of a direct armed conflict".
Nato responded by accusing Moscow of "irresponsible nuclear rhetoric" and said it posed no threat to Russia.
Moscow claimed Nato was preparing for potential military operations to blockade Kaliningrad, the Russian exclave bordering Poland and Lithuania, citing the defence alliance's exercises in the region and the Baltic Sentry mission to protect undersea infrastructure.
"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 stated.
Such moves could result in "Russian strikes against decision-making centres in the alliance's member states right from the outset of the conflict", it warned.
Kremlin spokesperson Dmitry Peskov told reporters it was "totally natural that our diplomats are trying to remind hotheads in Europe about our foundational documents on this issue", according to Interfax.
The Russian statements were in part a response to recent coverage of Kaliningrad in the UK media, including a documentary on Sky News about a fictional war-gaming exercise.
"I can confirm that Russia sent a non-paper to Nato and that we have sent a response, noting that Nato is a defensive alliance and none of our activities or exercises pose a risk to any part of Russia," said alliance spokesperson Allison Hart. "We strongly denounce the threat of force, including any irresponsible nuclear rhetoric."
"Russia's use of hybrid tactics is a sign of desperation. But we will not be dissuaded from our support to Ukraine," Hart added. "We have what it takes to defend every inch of Allied territory and remain strong, ready and able to counter any threat."
Kaliningrad has long been a source of tension between Russia and Nato, given its strategic location on the Baltic Sea, and the potential for Russia to cut off the three Baltic states from the rest of their Nato allies if they were to annex a land corridor between the exclave and its military ally Belarus.
Russia maintains a large naval fleet in the exclave and a wide range of missiles capable of striking the vast majority of Nato capitals, including nuclear-capable Iskander missiles.
The nuclear threats come as Belgium's defence minister Theo Francken warned of a "dark winter" ahead as a result of Russia's continuing campaign of hybrid attacks on Europe.
"There will be more hybrid threat actions in the coming months. It will be a dark winter for Europe," Francken said on Wednesday.
"Hybrid warfare is not something that Russia has started since two to three years," he added. "They have been doing it for 50 years. This is something that [President Vladimir] Putin is very good at ."