MOSCOW, May 13. /TASS/. Russia has declared an employee of the Bulgarian embassy to Moscow persona non grata in retaliation to a similar move Bulgaria made in April, the Russian Foreign Ministry said in a statement on Friday.

"On May 13, Bulgarian Ambassador Extraordinary and Plenipotentiary to Russia Atanas Krastin was summoned to the Russian Foreign Ministry to be presented with a note declaring an employee of the Bulgarian embassy to Moscow persona non grata," the ministry said in a statement.

"The measure is in retaliation to the non-motivated decision Bulgaria made in April to declare a diplomat from the Russian embassy to Sofia persona non grata", the ministry added.

On April 1, the Bulgarian Foreign Ministry declared the first secretary of the Russian embassy to Sofia persona non grata. Earlier that day, the Bulgarian prosecutor’s office informed Foreign Minister Teodora Genchovska of unregulated intelligence activities allegedly carried out by a Russian diplomat. The embassy’s first secretary was reportedly suspected, yet no evidence confirming the Russian diplomat’s illegal activities was provided to the diplomatic mission.