Russia launched its biggest missile and drone attack on Ukraine so far this year on Tuesday, according to Ukrainian authorities, cutting heat to tens of thousands of people and ending a brief reprieve agreed to by Moscow and Washington as Ukrainians grapple with plummeting winter temperatures.

The U. S. and Russia are barreling toward what could become the first unrestricted nuclear arms race since the Cold War, as the last remaining treaty limiting their nuclear arsenals is set to expire in a matter of days.