Russia said on Monday that everyone should be "very, very careful" about nuclear rhetoric, responding to a statement by U.S. President Donald Trump that he had ordered a repositioning of U.S. nuclear submarines.

In its first public reaction to Trump's comments, the Kremlin played down their significance and said it was not looking to get into a public argument with him.

Trump said on Friday he had ordered two nuclear submarines to be moved to "the appropriate regions" in response to remarks from former Russian president Dmitry Medvedev about the risk of war between the nuclear-armed adversaries.

"In this case, it is obvious that American submarines are already on combat duty. This is an ongoing process, that's the first thing," Kremlin spokesperson Dmitry Peskov told reporters.

"But in general, of course, we would not want to get involved in such a controversy and would not want to comment on it in any way," he said. "Of course, we believe that everyone should be very, very careful with nuclear rhetoric."

The episode comes at a delicate moment, with Trump threatening to impose new sanctions on Russia and buyers of its oil, including India and China, unless President Vladimir Putin agrees by Friday to end the 3½-year war in Ukraine.

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Putin said last week that peace talks had made some positive progress but that Russia had the momentum in the war, signaling no shift in his position despite the looming deadline.

Trump has said he may send his envoy Steve Witkoff to Russia on Wednesday or Thursday. Witkoff has held long conversations with Putin on several previous visits but failed to persuade him to agree to a ceasefire.

The Kremlin declined to say if his latest proposed trip was taking place at Moscow's request and did not say what it hoped might emerge from it.

"We are always happy to see Mr. Witkoff in Moscow and we are always happy to have contacts with Mr. Witkoff. We consider them important, meaningful and very useful," Peskov said.

Online spat

Trump, who frequently promised to end the war within 24 hours while campaigning for the U.S. presidency last year, has spoken admiringly of Putin in the past but voiced increasing frustration with him of late.

Russia has stepped up the ferocity of its bombing attacks on Ukrainian cities, while three brief sessions of direct peace talks in Turkey have yielded no progress beyond exchanges of prisoners and war dead.

Some security analysts in both Russia and the West have criticized Trump for escalating an online spat with former president Medvedev — an arch-hawk whose statements are frequently designed to shock and provoke — to the point of publicly discussing U.S. nuclear deployments.

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U.S. President Donald Trump declared a 50-day deadline on Russia to reach a ceasefire with Ukraine or face ‘very severe tariffs.’ Meanwhile, Trump also pledged renewed support for Ukraine — a move welcomed by NATO allies.

Peskov, however, said Russia did not see Trump's statement as marking an escalation in nuclear tension.

"We do not believe that we are talking about any escalation now. It is clear that very complex, very sensitive issues are being discussed, which, of course, are perceived very emotionally by many people," he said.

Peskov declined to answer directly when asked whether the Kremlin had tried to warn Medvedev to tone down his online statements.

"The main thing, of course, is the position of President Putin," he said.