The note also warns of possible Russian strikes on decision-making centres in NATO member states once a conflict begins. Reuters cited the document, which is described as unofficial.
It says Russia would be prepared to use its full range of available forces and capabilities to defend what it considers its territory. The note also alleges NATO has plans for an air and sea blockade of Kaliningrad. That is a Russian claim, not a confirmed NATO decision.
The document's status matters. It is unofficial, not a confirmed public policy decision.
Kaliningrad is a Russian exclave on the Baltic Sea, bordered by Poland and Lithuania. Its position makes land and sea logistics a central vulnerability and gives the region added significance in Russia-NATO relations.
Embassies accuse NATO of raising tensions
Russian embassies in at least three European countries issued statements over the past three days. They accused NATO of escalating tensions and pointed to military exercises and planning related to Kaliningrad.
The statements added a public diplomatic charge to the warning. In a written response reported by Reuters, NATO said its exercises and activities do not threaten Russian territory. The alliance urged Moscow to stop what it called irresponsible nuclear rhetoric.
At the time of the reports, there was no confirmation that NATO had decided to isolate the region. That remains unconfirmed.
NATO Secretary-General Mark Rutte said the alliance is defensive and urged Russia to stop making nuclear threats, describing the rhetoric as unnecessary and harmful.
A warning with high escalation stakes
The reported threat focuses on Kaliningrad. The document frames any attempt to isolate the region as a defence of Russian territory and links that scenario to possible nuclear use. It also describes possible strikes against decision-making centres after a conflict starts.
The warning is unofficial, not an adopted state decision. Still, language that links the defence of Kaliningrad to nuclear capabilities and attacks on NATO decision centres is a serious escalation signal. It is not evidence that such actions have been ordered.
