Russia's foreign ministry said on Monday it had expelled a Ukrainian diplomat in retaliation for Kyiv kicking out an employee of the Russian embassy earlier this month.
Russia and Ukraine expelled a diplomat each earlier this month after Moscow accused a Ukrainian consul in St. Petersburg of trying to obtain classified information.
Ukraine's foreign ministry called the decision "another provocation" and said that in the near future it would announce "on the basis of reciprocity" the expulsion of a Russian diplomat from country.
Relations between Moscow and Kyiv have been dire since Russia annexed the Crimean peninsula in 2014 and backed a pro-Russian separatist insurgency in east Ukraine.
Tensions have soared in recent weeks over a Russian military build-up near the Ukrainian border that raised alarm in both Kyiv and in the West.
Russia, which said the build-up had been part of military exercises, said last week it had begun returning the troops to their permanent bases.
(Reporting by Maxim Rodionov; additional reporting by Pavel Polityuk in Kyiv; Writing Gabrielle Tétrault-Farber; Editing by Gareth Jones)
