Russia declared two Bulgarian diplomats 'persona non grata' on Tuesday and ordered them to leave the country in response to Sofia's expulsion of two Russian diplomats last month for suspected espionage.

The action followed Russia's decision to kick out diplomats from the United States, Czech Republic and Poland in a flurry of expulsions within the past five days in retaliation for the barring of its own staff, reflecting a sharp deterioration in its relations with the West.

Kremlin spokesman Dmitry Peskov said on Tuesday that Russia was not to blame for the spike in tensions, and said foreign countries should refrain from "mass anti-Russia psychosis".

Bulgaria threw out the Russian diplomats in March after prosecutors charged six people, including current and former military intelligence officers, with spying for Russia. 

Russia's foreign ministry identified two employees at the Bulgarian embassy in Moscow and said it had ordered them to leave Russian territory within 72 hours.

Bulgaria's foreign ministry confirmed that its diplomats were declared 'persona non grata' and that the action was a direct response to its expulsion of Russian diplomats in March.

-No other reasons for the actions of the Russian authorities were pointed out at today's meeting- it said in a statement.