Russia’s former President Dmitry Medvedev has issued a sobering warning to Donald Trump after the US leader accused Vladimir Putin of “playing with fire”. US President Mr Trump, writing on his Truth Social platform, said: “What Vladimir Putin doesn’t realize is that if it weren’t for me, lots of really bad things would have already happened to Russia, and I mean REALLY BAD. He’s playing with fire!” The remark drew a sharp response from Mr Medvedev, now deputy chairman of Russia’s Security Council and one of Mr Putin’s most outspoken allies. Posting on X, formerly Twitter, he said: “Regarding Trump's...