President Vladimir Putin on Sept. 21 warned the West he was not bluffing when he said he would be ready to use nuclear weapons to defend Russia against what he said was "nuclear blackmail" from major Western powers.Register now for FREE unlimited access to Reuters.com"We express our daily regret that Western heads of state, in the United States and Europe, engage in nuclear rhetoric every day," Kremlin spokesman Dmitry Peskov said of Biden's interview to CNN.The NATO military alliance is proceeding with its annual nuclear preparedness exercise "Steadfast Noon" next week, in which NATO air forces practise the use of U.S. nuclear bombs based in Europe with training flights, without live weapons.Peskov said that remarks by NATO Secretary-General Jens Stoltenberg, who said that if Putin wins the war it would be a defeat for the West, showed that NATO was essentially fighting on Ukraine's side."As far as I know, there have been no initiatives from either the Russian or the American side to organize contacts at the highest level," Peskov said."