Estonia says it has expelled two Russian diplomats in the latest incident to strain relations between the two neighbors.
The Estonian Foreign Ministry made the announcement on May 26, without elaborating.
The Baltic News Service named the two diplomats as Dmitry Kazyonnov, Russia's consul-general in the city of Narva on the Estonian-Russian border, and consul Andrei Surgayev.
"This is another unfriendly and ungrounded move, which will not remain without a response," the Russian Foreign Ministry warned.
Relations between Russia and Estonia, a member of both the European Union and NATO, have been tense for years.
Earlier in May, an Estonian court sentenced a Russian citizen to five years in prison after finding him guilty of spying for Russia.
Based on reporting by Delfi, Interfax, TASS, AFP, and Reuters