By Mark Trevelyan
Sept 30 (Reuters) - Russia has warned NATO that it would be ready to resort to nuclear weapons if the Western alliance tried to cut off or attack the Russian region of Kaliningrad.
WHERE AND WHAT IS KALININGRAD?
It's a highly militarised exclave - separated from the main mass of Russian territory - that is wedged between NATO members Poland and Lithuania and also borders the Baltic Sea. It has a population of about 1 million and is slightly bigger in area than the US state of Connecticut.
HOW DID IT COME TO BE RUSSIAN?
Kaliningrad, formerly the German city of Königsberg and capital of East Prussia, became part of the Soviet Union after the Red Army captured it in April 1945 and the victorious allies divided East Prussia at the end of World War Two.
WHAT MAKES IT STRATEGICALLY IMPORTANT?
It provides Russia with a platform for air defence, missile and naval forces that can project power deep into northern and central Europe. At the same time, it is a potentially vulnerable pressure point for Moscow because of its boxed-in location between two NATO states and the difficulty of maintaining supply lines or reinforcing it in the event of a war.
WHAT HAS LED TO THE LATEST SPIKE IN TENSIONS?
These have been rising steadily since Russia's 2022 invasion of Ukraine, which led NATO to move decisively to strengthen its eastern flank. The alliance has expanded in the region, with Finland and Sweden joining in 2023 and 2024 respectively.
Russia perceives a growing Western threat to Kaliningrad. In May 2026, it slammed remarks by Lithuania's foreign minister as "verging on insanity" after he said NATO had to show Moscow it was capable of "penetrating the small fortress they've built in Kaliningrad" and razing Russian air defences and missile bases there.
A Western military source told Reuters that dozens of aircraft from NATO members were involved in an unannounced operation in the airspace around Kaliningrad in mid-August, demonstrating the capability to cut off the exclave's radio and radar links as well as its air defences in the event of a conflict with Russia.
In social media posts, Russian embassies in Europe have highlighted what Moscow sees as threatening NATO military movements in the Baltic and hawkish rhetoric on Kaliningrad from policymakers and in the media.
NATO says it has increased its presence in the Baltic Sea partly in response to concerns about threats to critical undersea energy and communications infrastructure. In its response to the Russian warning, it urged Moscow to halt its "increasingly reckless behaviour" and "irresponsible nuclear rhetoric".
WHAT DO EXPERTS FEAR COULD SPARK A CRISIS?
European states have been walking a fine line since 2022 - supporting Ukraine with weapons, intelligence and sanctions against Russia while stopping short of joining the conflict themselves - though Moscow said this week they are already "waging war" against it.
Security analysts say any miscalculation could lead to a direct military confrontation - and Kaliningrad, by virtue of its location, would be a potential flashpoint.
Among the possible triggers could be drone incidents, disruption of critical infrastructure, major new missile deployments or anything perceived by Moscow as amounting to a NATO attempt to impose a blockade on the exclave.
(Additional reporting by Sabine Siebold in Karlsruhe, GermanyEditing by Gareth Jones)
