Former President Trump issued a warning to Dmitry Medvedev, Russia’s ex-president, cautioning him about the risks of “dangerous territory” after Medvedev criticized the US-imposed deadline for a cease-fire in Ukraine, calling it “a step towards war.”

Trump commented, “Tell Medvedev, the failed former President of Russia, who seems to think he still holds office, to be cautious with his words. He is treading into very dangerous territory!” His remarks were directed at Medvedev, a key ally of Russian President Vladimir Putin, and were posted on Truth Social on Thursday morning.

Earlier, on Monday, while speaking to reporters in Scotland, Trump announced he was shortening a previously given 50-day ultimatum to Russia, urging for the cessation of the three-year conflict in Ukraine within the next 10 to 12 days.

He gave Putin the original 50-day target time on July 14 and called for a peace agreement to be made between the two neighboring countries, or face economic punishment. 

Medvedev, Russia’s Security Council deputy chairman, claimed the two superpowers were heading towards a war of their own if the US commander in chief continued his push to end the war.

“Trump’s playing the ultimatum game with Russia: 50 days or 10 … 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,” Medvedev, 59, wrote to X on July 28.

The 78-year-old president invoked India in his response to Medvedev hours after he imposed a 25 percent tariff plus “penalty” on the country, which is set to begin on August 1.

“I don’t care what India does with Russia. They can take their dead economies down together, for all I care. We have done very little business with India, their Tariffs are too high, among the highest in the World,” Trump wrote on Truth Social.

“Likewise, Russia and the USA do almost no business together. Let’s keep it that way,” he added.

Trump says he has been disappointed with his Russian adversary, who has failed to end the deadly incursion.

“I’m disappointed in him, I must be honest with you,” the commander in chief told The Post’s Miranda Devine, on the newest episode of “Pod Force One,” released Wednesday. 

“We’ve had great conversations, but it hasn’t been followed up with, you know, just some very bad things have happened. Very, very bad things have happened after we’ve had conversations.  And I’d leave and I’d say, ‘Well, I really thought we had it settled’ three or four times.”