Threats, low expectations cloud start of U.S.-Russia talks over Ukraine

The United States and Russia began high-stakes security talks on Monday, launching a diplomatic effort to defuse soaring tensions over a Russian military buildup on its border with Ukraine. 

But a breakthrough appeared unlikely, with Moscow's threats and low expectations from both sides clouding the possibility of an end to fears Russia is planning to invade its neighbor.

Ahead of a flurry of diplomatic activity in Europe this week, Deputy Secretary of State Wendy Sherman was holding face-to face talks with Russian Deputy Foreign Minister Sergei Ryabkov at the U.S. diplomatic mission in Geneva, Switzerland.

Ryabkov warned Sunday...