Bulgaria's Foreign Ministry on Thursday told a Russian diplomat to leave the country amid investigations into a series of explosions at Bulgarian arms depots.

It's the latest move in a growing diplomatic dispute between Russia and several former Soviet-bloc countries.

It also follows the Czech Republic's accusations that Russia was behind an arms depot blast in the country in 2014.

What did Bulgaria say?

Foreign Minister Ekaterina Zaharieva announced the expulsion following talks with Russia's ambassador.

In a statement, Zaharieva urged Russia's full cooperation in Bulgaria's investigation of the four explosions — as well as a probe into the poisonings of three Bulgarian citizens, including arms trader Emilian Gebrev.

"Bulgaria wants to keep equal and mutually beneficial relations with Russia and that is why it insists on an active and result-orientated cooperation from Russia to shed light on the circumstances around the incidents," the statement read.

Zaharieva also said Bulgaria reserves the right to take further retaliatory steps.

How did Russia respond?

Shortly after the announcement, Russia's Foreign Ministry said it would respond to the expulsion, Interfax news agency reported.

The report did not provide further details on how Russia plans to respond.

Russia has denied any wrongdoing and dismissed the Bulgarian investigation.

What happened with the arms depot blasts?

On Wednesday, Bulgarian prosecutors said they suspected six Russians were involved in a series of munitions explosions.

The explosions at Bulgarian arms depots took place between 2011 and 2020. At the time, the depots were storing munitions that were meant to be exported to Ukraine and Georgia.

The prosecutors also said they suspected the Bulgarian blasts were connected to the attempted murder of arms dealer Gebrev, as well as a 2014 arms depot blast in the Czech Republic.

Three suspects, who are believed to belong to Russia's military intelligence service GRU, have already been charged over the poisonings.

Separately, Bulgaria has expelled a total of eight Russian diplomats over alleged espionage since October 2019.

Earlier this month, six people were arrested over alleged involvement in a Russian spy network.

rs/sms (Reuters, IFAX)