EXPLAINER: Putin’s Ukraine strategy mixes threats, diplomacy

MOSCOW (AP) — With Russia carrying out a massive military buildup near Ukraine and the West roundly rejecting Moscow’s security demands, a window for diplomacy in the crisis appears to be closing.But even as Moscow continues to bolster its forces and holds sweeping war games, President Vladimir Putin is keeping the window open for more negotiations in a calculated game of brinkmanship intended to persuade Washington and its allies to accept Russia's demands.