Ukrainian foreign ministry alleged 80 Russian forces invaded a village just north of Crimea.
Russia vetoed a U.N. Security Council resolution against Sunday's referendum in Crimea.
The vice president will discuss Ukraine's unrest with European leaders.
Americans in the region were encouraged to stay vigilant.
Resolution also calls for end to attacks on Syrian civilians and more humanitarian access.
Secretary of State is accused of fomenting street protests.
A Republican and Democrat in the House are calling on President Obama to sanction more Russian officials for human rights abuses.
The senator writes that Russians will be inspired to follow Ukraine's example.
The Obama administration is pursuing a free trade agreement with Vietnam, but critics of the country’s authoritarian regime believe sanctions are in order.
House Foreign Affairs Committee Chairman Ed Royce (R-Calif.), a vocal champion of human rights, on Friday introduced a bill that would impose targeted financial and visa sanctions on Vietnamese individuals involved in abuses.
The number is the highest recorded since the breakup of the Soviet Union.