Dmitry Medvedev, a long-time ally of Russian President Vladimir Putin, has laid out the country's new deterrence policy against Western "aggression," and warned that provocations by Ukraine and its allies could result in nuclear war.

President Vladimir Putin says any nation’s conventional attack on Russia that is supported by a nuclear power will be considered a joint attack on his country.

President Vladimir Putin warned the West on Wednesday that Russia could use nuclear weapons if it was struck with conventional missiles, and that Moscow would consider any assault on it supported by a nuclear power to be a joint attack.