Top US national security officials have spoken with their Ukrainian counterparts, and America’s top general held a call Wednesday with his Russian opposite number amid concern over Russian military activity in Crimea and eastern Ukraine, including what the US deemed a violation of a ceasefire by Moscow that led to the deaths of four Ukrainian soldiers last week.Top US national security officials have spoken with their Ukrainian counterparts, and America’s top general held a call Wednesday with his Russian opposite number amid concern over Russian military activity in Crimea and eastern Ukraine, including what the US deemed a violation of a ceasefire by Moscow that led to the deaths of four Ukrainian soldiers last week.