Medvedev threatened Trump with WWIII, Kellogg responded

Russian Security Council Deputy Chairman Dmitry Medvedev responded to US President Donald Trump's statement, who had earlier criticized Vladimir Putin, saying that "he is playing with fire, and very bad things will happen to Russia." Medvedev threatened Trump with World War III.

"Regarding Trump's words about Putin "playing with fire" and "really bad things" happening to Russia. I only know of one REALLY BAD thing — WWIII.
I hope Trump understands this!", Medvedev wrote.

In response, US Special Representative for Ukraine Keith Kellogg said:

"Stoking fears of WW III is an unfortunate, reckless comment by
Medvedev and unfitting of a world power. President Trump
is working to stop this war and end the killing. We await receipt of RU Memorandum (Term Sheet) that you promised a week ago. Cease fire now".