The two diplomats were given 72 hours to leave Bulgaria.

“Their aim was to hand over the information collected, which is a state secret, to the Russian military intelligence services (GRU) in Moscow,” a statement from the Bulgarian Prosecutor’s Office said.

The two Russian diplomats were assisted by two Bulgarians who have access to information about the Bulgarian military industry and who, on certain occasions, were paid for their services, according to the Prosecutor’s Office.

Bulgaria, a NATO member since 2004 and the EU since 2007, has traditionally maintained close political and economic relations with Moscow, but espionage cases involving Russian citizens have multiplied in recent years.

A Russian diplomat was expelled from Bulgaria in October 2019 due to espionage. He is a high-ranking secretary looking for information on the interests of Bulgaria, NATO and the EU. Prior to the case, Sofia had arrested a former Bulgarian parliamentarian accused of money laundering and espionage for a Russian secret service and banned two Russian citizens seeking to subversively influence the course of Bulgaria’s foreign policy. Sofia is now looking for three GRU agents accused of poisoning a Bulgarian businessman with Noviciok, the poison used against former double spy Sergei Skripal and recently against Russian opponent Aleksei Navalny.

Bulgaria, a former satellite of the USSR, still has Soviet weapons, but is trying to modernize its army. Eight F-16s, bought in July, are to be delivered in 2024 as part of a NATO modernization program.