Russia said on Saturday that the accelerated deployment of modernised B61 tactical nuclear weapons at NATO bases in Europe by the U.S would lower the 'nuclear threshold'. Russian Deputy Foreign Minister Alexander Grushko told state RIA news agency that the plans to modernize nuclear weapons, 'those free-fall bombs that are in Europe', cannot be ignored. Moscow has warned that it would take such a move by the U.S into account during its military planning. The war in Ukraine has triggered the biggest confrontation between Russia and the U.S since the 1962 Cuban Missile Crisis when the two Cold War superpowers came closest to nuclear war.