Estonia said Monday it would expel the Russian ambassador from Tallinn in retaliation for Moscow's expulsion of the Estonian ambassador.
Tensions between Russia and its European neighbours have spiked since Moscow invaded Ukraine last year.
"We stand by the principle of parity in relations with Russia," the Estonian ministry of foreign affairs said in a tweet sent in English, adding that the Russian ambassador would have to depart at the same time as his Estonian counterpart, ordered by Moscow to leave on February 7.
Russia's foreign ministry said in a statement issued on Monday it downgraded its diplomatic relations with Estonia, accusing the Baltic country of "total Russophobia."
The measures come after Estonia drastically reduced staff levels at Russia's embassy in Tallinn, Moscow's statement said.
"Russia's steps will not deter us from providing continued support to Ukraine," Estonian Foreign Minister Urmas Reinsalu said in a tweet following tit-for-tat response from Tallin.
