Russia's nuclear warning over Kaliningrad is an attempt to deter NATO rather than evidence of an imminent attack

Security arrangement under which states commit to treat an attack on one as an attack on all, obliging joint response. Underpins alliances such as NATO and provisions of the UN Charter, making shared deterrence and coordinated military planning central instruments of international stability.

Putin said a direct attack on Kaliningrad would put the use of Russia's full arsenal, including nuclear weapons, on the agenda. The statement is a conditional warning; Reuters reported no new nuclear deployment or strike decision.