Ukraine has banned Russian men between the ages of 16 and 60 from entering the country.
Ukrainian President Petro Poroshenko announced the decision on Twitter Friday. He said it is part of an effort to stop Russia from forming "private armies" on Ukraine's soil.
The move comes just a few days after Ukraine declared martial law in response to Russia seizing three of its naval vessels off the coast of the Crimean Peninsula. The measure will last 30 days and only impact certain regions.
Poroshenko said martial law would help strengthen Ukraine's defenses amid increasing tensions with Russia. Russia responded to the command, saying it is not planning any retaliation.
Additional reporting from Newsy affiliate CNN.