Security has been tightened all along the perimeter of the Ukrainian state border, the State Border Service said.

"The state border service is on alert. We have not been observing any movement of troops in the neighboring territory near the Ukrainian border," Border Service spokesman Serhiy Astakhov told Interfax-Ukraine.

Leader of the Svoboda movement's parliamentary faction Oleh Tiahnybok told the parliament's conciliatory council, citing his sources, that Russian troops are concentrated near the Ukrainian border.