President Trump said on his social media feed on Friday that he had “ordered two nuclear submarines to be positioned” in regions within reach of Russia, a rare threat of nuclear escalation that he said was prompted by online threats from Russia’s former president, Dmitri Medvedev.
Mr. Trump said he had ordered the submarines “to be positioned in the appropriate regions, just in case these foolish and inflammatory statements are more than just that.” He added: Words are very important, and can often lead to unintended consequences, I hope this will not be one of those instances.”
Mr. Medvedev, who often serves as something of an online attack dog for the Kremlin, had said in a social media post of his own on Thursday that Mr. Trump should picture the apocalyptic television series “The Walking Dead” and referred to the Soviet Union’s system for launching a last-ditch, automatic nuclear strike.
Because nuclear submarine movements are among the Pentagon’s most closely held tactical maneuvers, it will most likely prove impossible to know if Mr. Trump is truly repositioning the submarines, or just trying to make a point.
But in Mr. Trump’s sudden and escalating confrontation with Russia over Ukraine, it is the first time he has referenced the American nuclear arsenal, much less threatened to reposition it. Mr. Trump said on Thursday that he intends to impose new sanctions on Russia over its unwillingness to wind down its war in Ukraine, the latest step in his gradual shift toward a more antagonistic stance toward the Kremlin.
Still, such public flexing of nuclear muscles is rare even for Mr. Trump, who last made explicit nuclear threats to Kim Jong Un of North Korea early in his first term, in 2018. At that time he said his “nuclear button” was “much bigger and more powerful” than Mr. Kim’s. That exchange ultimately led to a diplomatic opening to Mr. Kim, three meetings between the two leaders — and a complete failure of the effort to get the North Korean leader to give up his nuclear arsenal, which is now larger than ever.
But Russia is a different case, and Mr. Trump has often talked about the fearsome power of nuclear weapons, something he contends he learned about from an uncle who was on the MIT faculty. So while President Vladimir V. Putin of Russia has made threats about putting nuclear forces on alert during the opening days of the Ukraine war, and may have been preparing to use a tactical nuclear weapon in the fall of 2022 against a Ukrainian military base, the U.S. has never responded.
Mr. Medvedev is a good foil for Mr. Trump; he regularly issues threats against the United States, but is essentially powerless. Mr. Trump has referred to Mr. Medvedev’s martial-sounding statements several times in the past week.
It was not clear what kind of nuclear submarines Mr. Trump was referencing. The U.S. has nuclear-powered attack submarines that search for targets, but it also has far larger, nuclear-powered and nuclear-armed submarines. Those don’t need to be repositioned; they can reach targets thousands of miles away.
Kingsley Wilson, the Pentagon press secretary, referred all questions about Mr. Trump’s statement to the White House.