Ukraine's top security adviser to President Volodymyr Zelenskiy criticized Russia's plans to station tactical nuclear weapons in Belarus, stating it would destabilize the country and increase negative sentiment towards Moscow.

Russian President Vladimir Putin announced the decision on Saturday as a warning to NATO, escalating tensions with the West.

Although not entirely unexpected, this marks one of Russia's most significant nuclear moves since invading Ukraine 13 months ago. Oleksiy Danilov, head of Ukraine's National Security and Defence Council, called the decision "a step towards internal destabilization" and accused Russia of taking Belarus as a "nuclear hostage."

Putin compared his plans to the US deploying weapons in Europe, clarifying that Russia would not transfer control of the weapons to Belarus. However, this could be the first time Russia has based such weapons outside its borders since the mid-1990s, a notable development given that the country has previously emphasized its lack of nuclear deployments abroad.

Another senior Zelenskiy adviser, Mykhailo Podolyak, dismissed Putin's plan as predictable and an indication of his fear of losing. US administration officials downplayed concerns about Putin's announcement and potential use of nuclear weapons in Ukraine.

Washington-based Institute for the Study of War (ISW) also assessed the risk of escalation to nuclear war as "extremely low." However, the International Campaign to Abolish Nuclear Weapons labeled Putin's announcement as an extremely dangerous escalation.

Meanwhile, Putin denied forming a military alliance with Beijing and claimed that Western powers were building a new "axis" similar to Germany and Japan's alliance during World War II. As fighting continues in Ukraine, the country's forces have managed to counter Russia's offensive in and around the eastern city of Bakhmut, stabilizing the situation.