Vladimir Putin says Russia has already stationed a first batch of tactical nuclear weapons in Belarus.
During a forum, Russia’s president said they would only be used if there was a threat to Russia’s territory or state.
There is no indication that the Kremlin plans to attack Ukraine with nuclear weapons, according to the US government.
After Mr Putin’s comments, US Secretary of State Antony Blinken said: “We don’t see any indication that Russia is preparing to use nuclear weapons.”
Last year, Mr Putin’s full-scale invasion of Ukraine was launched from Belarus, a key Russian ally.
By the end of the summer, Putin said, the tactical nuclear warheads would be transferred.
He said the move was about containment and to warn anyone thinking of inflicting a strategic defeat on Russia.
In response to a question from the forum’s moderator, he responded: “Why should we threaten the entire world? I have already said that extreme measures might be used if Russian statehood is threatened.”
Nuclear tactical weapons are small, lightweight warheads and delivery systems designed to destroy enemy targets within a specific area without causing widespread radioactive fallout.
Nuclear weapons can be as small as one kiloton (producing the equivalent of a thousand tonnes of TNT). They can also be as big as 100 kilotons, comparable to the 15 kilotons dropped on Hiroshima in 1945.
Is it possible for Russia to use tactical nuclear weapons?
After visiting Kyiv on Friday, the Russian leader will meet African leaders in St Petersburg to present a peace initiative to both countries.
While they were in the city, Russian missiles attacked it.
Both sides should de-escalate and engage in peace negotiations, said South African President Cyril Ramaphosa.
“We came here to listen and acknowledge the suffering of the Ukrainian people,” he said.
Volodymyr Zelensky, the president of Ukraine, said that instead of making diplomatic overtures to Russia, it should be frozen out diplomatically.
Mr Zelensky said Kiev would not negotiate with Moscow while it still occupied Ukrainian territory.
Putin also reiterated his claim that Ukraine’s ongoing counteroffensive had no chance of success.
Furthermore, the Ukrainian military was running out of its own equipment and would soon be relying solely on Western donations.
There is no doubt that any F16 US fighter jets given to Ukraine will burn, he warned.
Asserting they are making progress in both eastern and southern Ukraine, the Ukraine has previously dismissed similar remarks.
Hanna Malyar, Ukraine’s Deputy Defence Minister, announced Friday that units had advanced 2 kilometers in all directions in the south of the country.
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In addition to economic themes, the Russian leader asserted that Western sanctions on Russia had failed to isolate it and that it instead expanded its trade with “the future markets”.
New deals with Asia, the Middle East, and Latin America were praised as “reliable, responsible partners.