Russia said on September 8 that it was ordering a Romanian diplomatic out of the country in response to a recent expulsion by Bucharest.
Romanian authorities expelled a Russian diplomat last month, citing a breach of international norms, and Russia's Foreign Ministry confirmed the diplomat's departure.
Moscow has deemed Romania along with other EU member states to be an "unfriendly" country, a designation introduced amid unprecedentedly tough sanctions to punish Russia's unprovoked invasion of Ukraine in February.
Hundreds of diplomats from both sides have been expelled since.
In April, Romania expelled 10 Russian Embassy employees in Bucharest at once, prompting a tit-for-tat move by Moscow.