Despite Russian reassurances that Moscow’s troop buildup along Ukraine’s eastern frontier is for a military exercise, its growing scale is making U.S. officials nervous about its ultimate aim. President Barack Obama on Friday urged ...

Pentagon officials say they believe there could be close to 50,000 Russian troops bordering the former Soviet republic and inside Crimea, recently seized and annexed by Moscow. That estimate is double earlier assessments, and ...

Washington got those assurances that the Russian troop buildup was only an exercise from Russian Defense Minister Sergei Shoigu a week ago. But no one in the U.S. government knows if Putin agrees — ...

There is no plan to involve the U.S. military in what is happening in Ukraine, even if Russia takes more territory. Ukraine borders Russia, and Ukraine does not belong to NATO, where an attack ...