Russia has warned Nato it would be ready to resort to nuclear weapons if the Western alliance attempted to cut off Kaliningrad, a Russian exclave that borders the Baltic Sea. In a document sent to Nato and seen by Reuters, Moscow accused the alliance of a “dangerous and reckless course” that entailed “high risks of the outbreak of a direct armed conflict”. The document said this included the possibility of “Russian strikes against decision-making centres in the alliance’s member states right...