Moscow has warned Donald Trump against resuming the testing of nuclear weapons when he takes office, saying it would “not rule anything out” in response to US aggression. Sergei Ryabkov, Russia’s deputy foreign minister who oversees arms control, noted that Mr Trump refused to ratify the Comprehensive Nuclear-Test-Ban Treaty during his first term. Referencing this refusal, Mr Ryabkov said: “American policy in its various aspects is extremely hostile to us today.” “So the options for us to act in the interests of ensuring security and the potential measures and actions we have to do this - and to send politically...