Former Russian leader Dmitry Medvedev has warned that the country’s rivals now faced a “new reality” as the Kremlin formally announced it was no longer bound by a treaty limiting the use of short and medium-range nuclear missiles.

Medvedev, who today serves as the deputy chairman of the country’s Security Council and is known for issuing frequent apocalyptic threats on social media, was continuing a war of words that prompted President Donald Trump to redeploy two nuclear submarines last week.

His latest warning came after the Russian Foreign Ministry announced it would no longer abide by the Intermediate Nuclear Forces Treaty, or INF, an agreement banning Washington and Moscow from deploying ground-based missiles with ranges between 500 to 5,500 kilometers (311 to 3,418 miles). It also comes days before the expiration of Trump’s deadline ultimatum for Russia to agree to a ceasefire or face additional tariffs.

The INF was already obsolete, with the United States accusing Russia of violating the pact for decades and itself withdrawing from the agreement in 2019, and Russia has made little secret of its use of these missiles during its war with Ukraine.

On Monday the Russian Foreign Ministry said it was formally abandoning any “efforts to maintain restraint in this area” because the U.S. was moving to deploy similarly ranged weapons systems to Europe and Asia.

Russia “no longer considers itself bound by the corresponding previously adopted self-restrictions,” it said.

Medvedev said the withdrawal from the INF was “the result of NATO countries’ anti-Russian policy” — a reference to Moscow’s longstanding claim that the Western military alliance is aggressively encircling Russia. “This is a new reality all our opponents will have to reckon with. Expect further steps.”

NBC News has contacted NATO for comment on his remarks.

Last week the former Russian leader became involved in a social media spat with Trump.

While in Scotland, Trump reduced his initial 50-day deadline for Russia to cease fighting, instead giving it 10-12 days. Medvedev responded by saying that “each new ultimatum is a threat and a step towards war” between Russia and the U.S.

On Friday Trump reacted by ordering two nuclear submarines to be deployed to “appropriate regions, just in case these foolish and inflammatory statements are more than just that.”

This social media back-and-forth is playing out as Russia makes slow, grinding gains on the battlefield in eastern Ukraine.

From the skies, Ukrainian civilians endured another hellish night of Russian drone and missile attacks, as well as shelling on the Zaporizhzhia, Kharkiv, Sumy, Kherson and Donetsk regions. Over the past 24 hours at least 15 civilians were killed, officials said.

Ukrainian President Volodymyr Zelenskyy thanked Trump for putting pressure on the Kremlin.

“Russia is dragging out the war against Ukraine for one reason only — it has the money to keep the war going,” he said in his nightly address Monday. “All sanctions that restrict Russia help bring peace. All weapons that strengthen Ukraine help bring peace. All political actions that isolate Russia help bring peace.”

Vocing an opinion common among Western experts on Russia, Mark Galeotti, warned against reading too much into comments by Medvedev.

“Medvedev is a professional troll these days. Trying to dig too much meaning into his various iterations is a fool’s errand,” said Galeotti, the British-based director of the consultancy Mayak Intelligence. “Indeed, sometimes I wonder if his statements are precisely intended to tie us into knots as we try to interpret them!”