"We have once again called on Sofia to stop participating in the politically motivated campaigns that are being pursued at the behest of Western countries or organisations ... This does not meet the interests of the Bulgarian people. Most likely, such steps and actions are stimulated from outside Bulgaria", Zakharova said at a briefing.
The spokeswoman slammed Sofia for failing to provide any evidence to substantiate the decision to declare the diplomats persona non grata. She also recalled this was "the fifth similar incident in the past 1.5 years."
On 22 March, Bulgaria declared two Russian diplomats suspected of links to an espionage case persona non grata.
Earlier the same month, the Bulgarian Prosecutor's Office said it started pre-trial proceedings against a group of people suspected of spying for Russia. The office also brought espionage charges against six Bulgarian citizens, including servicemen and public servants, who allegedly transferred classified data to Russia.
Moscow warned that it reserved the right to a tit-for-tat response to Bulgaria's decision.