The Ukrainian State Border Service has tightened control of the eastern part of Ukraine's border in light of the terror attacks on Russia's Volgograd, the Border Service told Interfax.

"Control of the eastern section [of the border] with Russia has been tightened," it said.

In addition, Ukraine will increase the number of Border Service officers deployed at the checkpoints to avoid lines in the run-up to the New Year's and Orthodox Christmas holidays, it said.