MOSCOW — Russia on Tuesday ordered two Bulgarian diplomats to leave the country within 72 hours, a move that comes a month after Bulgaria expelled two Russian diplomats over espionage accusations.

Russia’s Foreign Ministry summoned Bulgarian Ambassador Atanas Krystin and informed him that two diplomats have been declared persona non grata in Russia. The decision was made in “response to an unwarranted decision made by the Bulgarian side in March this year to declare two employees of the Russian Embassy in Sofia persona non grata,” the ministry said in a statement.

On March 22, Bulgaria’s Foreign Ministry announced the expulsion of two Russian diplomats accused by Bulgarian prosecutors of espionage. The prosecutors said in a statement that a pre-trial investigation established that “two Russian citizens with diplomatic immunity have carried out illegal intelligence activities.”

The expulsions were linked to a raid last month that saw authorities detain six people and charge them with delivering classified NATO-linked information to the Russian embassy in Sofia. Later, one of them offered to cooperate with the authorities and was released on bail.

Prosecution spokeswoman Siika Mileva said the alleged ringleader had graduated from the intelligence school in Moscow run by Russia’s GRU military intelligence agency.

Russia’s embassy was quick to brush off the spying allegations, calling them part of “incessant attempts to drive a wedge in the Russian-Bulgarian dialogue and again demonize our country.”