Trump posted on his social media site that based on the “highly provocative statements” from Medvedev he had “ordered two Nuclear Submarines to be positioned in the appropriate regions, just in case these foolish and inflammatory statements are more than just that.”

The president added, “Words are very important, and can often lead to unintended consequences, I hope this will not be one of those instances.”

It wasn’t immediately clear what impact Trump’s order would have on US nuclear subs, which are routinely on patrol in the world’s hotspots, but it comes at a delicate moment in the Trump administration’s relations with Moscow.

Trump has said that special envoy Steve Witkoff is heading to Russia to push Moscow to agree to a ceasefire in its war with Ukraine and has threatened new economic sanctions if progress is not made.

He cut his 50-day deadline for action to 10 days, with that window set to expire next week.

The post about the sub repositioning came after Trump, in the wee hours of Thursday morning, had posted that Medvedev was a “failed former President of Russia” and warned him to “watch his words.”

Medvedev responded hours later by writing, “Russia is right on everything and will continue to go its own way.”

Medvedev was president from 2008 to 2012 while Putin was barred from seeking a second consecutive term but stepped aside to let him run again.

Now deputy chairman of Russia’s National Security Council, which Putin chairs, Medvedev has been known for his provocative and inflammatory statements since the start of the war in 2022, a U-turn from his presidency, when he was seen as liberal and progressive.

He has frequently wielded nuclear threats and lobbed insults at Western leaders on social media.

Some observers have argued that with his extravagant rhetoric, Medvedev is seeking to score political points with Putin and Russian military hawks.

Trump and Medvedev have gotten into online spats before.

On July 15, after Trump announced plans to supply Ukraine with more weapons via its NATO allies and threatened additional tariffs against Moscow, Medvedev posted, “Trump issued a theatrical ultimatum to the Kremlin.”

“The world shuddered, expecting the consequences. Belligerent Europe was disappointed. Russia didn’t care.”

Earlier this week, he wrote, “Trump’s playing the ultimatum game with Russia: 50 days or 10″ and added, “He should remember 2 things: 1. Russia isn’t Israel or even Iran. 2. Each new ultimatum is a threat and a step towards war.

“Not between Russia and Ukraine, but with his own country.”