Russia's Foreign Ministry said it will expel a Montenegrin diplomat in response to the Balkan country's own expulsion of a Russian official in the wake of the nerve-agent poisoning incident in Britain.
The move, announced on April 2, was the latest in the tit-for-tat expulsions between Moscow and several other, mostly Western, countries.
It follows Britain's conclusion that the Russian government was responsible for the near-fatal poisoning of ex-Russian double agent Sergei Skripal last month.
To date, 150 Russian diplomats have been ordered to leave by two dozen countries in the West.
Despite historic linguistic, religious, and economic ties, relations between Moscow and Podgorica have steadily worsened as Montenegro has sought closer relations with the West.
Montenegro's accession to NATO was met with an angry response by Moscow. Montenegrin authorities have accused Russian intelligence of being behind an attempted coup in 2016.
Skripal remains hospitalized in critical condition; his daughter Yulia has partially recovered.