'Keep the defender guessing': Russia's military options on Ukraine

The United States said it feared Russia was preparing a pretext to invade Ukraine if diplomacy fails to meet its objectives, after a massive cyberattack splashed Ukrainian government websites with a warning to "be afraid and expect the worst".

Moscow dismissed such warnings, though it has amassed more than 100,000 troops on its neighbour's frontiers and on Friday released pictures of more of its forces on the move.