Estonia's Foreign Ministry confirmed on Monday it has expelled two Russian diplomats in the small Baltic country's run-up to Nato and EU entry.
"Yes, we confirm that Estonia's Ministry of Foreign Affairs expelled two Russian diplomats last week and declared them persona non grata in Estonia," a ministry spokeswoman said, but declined any further comments.
A newspaper had reported on Saturday that the two diplomats were expelled for spying.
The Russian Foreign Ministry declined to comment on the confirmation of the expulsions from Tallinn.
The incident will likely worsen an already uneasy relationship between Moscow and Estonia, due to join Nato in April and the European Union in May, and follows a recent case in Baltic neighbour Lithuania, where three Russian diplomats were thrown out last month for spying.
Newspaper Eesti Paevaleht, citing unnamed sources, said on Saturday the two were ordered out last Wednesday and had left, and Tallinn expected Russia to retaliate with a tit-for-tat expulsion. The paper said the Russians were low-level diplomats.
Estonia's former ambassador to Russia, Mart Helme, was quoted as saying the two diplomats had probably been testing Estonia's ability to protect classified information as it prepares to join Nato.
Estonia, an ex-Soviet republic of just 1.2 million people, has made sweeping democratic and free-market reforms since independence in 1991 for its return to mainstream Europe.
Relations with Moscow have remained difficult, with Tallinn complaining about Russian interference and Moscow voicing concerns about the treatment of Estonia's large ethnic Russian minority which came to live and work there in the Soviet era.
Estonia expelled two Russian diplomats in 2000 and one in 1996, all for spying.