The ministry said that Russian diplomat has 72 hours leave the country.
Bulgaria's foreign ministry said Friday that it would expel another Russian diplomat on suspicion of spying, just two weeks after the Balkan country declared ten Russian diplomats 'persona non grata'.
"The foreign ministry handed a note declaring the diplomatic official 'persona non grata', giving him a 72-hour deadline to leave the country," the ministry said in a statement.
The move followed an alert by the Bulgarian prosecution that the diplomat -- a first secretary at Russia's embassy in Sofia -- was "involved in unregulated intelligence activity" by collecting "information of national importance," the prosecution said in a statement earlier Friday.
Specialised prosecutors announced that two mid-level officers at Bulgaria's counter intelligence State Agency for National Security (SANS) and a third ministerial official were being investigated for suspected spying for Russia, without giving further details.
SANS chief Plamen Tonchev said at a subsequent news conference that the two long-time officers -- a sector chief and a department chief -- were suspended from work after an internal investigation at the agency revealed that one of them was "working in the interest of Russia".
Tonchev hinted that revelations would see "more (Russian diplomats) declared 'persona non grata' in Bulgaria ... after this case."
Bulgaria already expelled ten Russian diplomats on March 18, amid a series of expulsions of Russian diplomats from European countries in the aftermath of the February 24 Russian invasion of Ukraine.
The EU and NATO member -- a once staunch ally of the Soviet Union under communism -- still has very close cultural, historic and economic ties with Russia.
But a series of espionage scandals since 2019 has soured relations between the two countries and seen some 20 diplomats and a technical assistant expelled.
Sofia also recalled its ambassador to Russia last week for consultations amid angry exchanges between its Prime Minister Kiril Petkov and the Russian envoy to Sofia Eleonora Mitrofanova in recent weeks.
Petkov said he expected that Russia would also recall Mitrofanova but there was no indication by Friday that Moscow would do that.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)