Ukraine crisis: Cease-fire threatened as nations toughen stances

Putin discusses Ukraine with Lukashenko, mocks upcoming peace conference hosted by Switzerland

Ukraine-Russia news live: Putin's troops reach outskirts of Kyiv as Chernobyl 'exceeds control level'

Putin threatens Ukraine with nuclear missiles

'They were drills and not a threat'

Why Putin invaded Ukraine: Russia's leader goes to war after stoking conflict

Sanctions expected after Russia recognizes breakaway Donbas region of Ukraine

Putin faces new sanctions as his war on Ukraine continues