SOFIA, Bulgaria — The prosecutor general’s office in Bulgaria announced Wednesday that it was investigating a possible connection between a series of explosions at ammunition depots around the country and an elite group of Russian military intelligence operatives known as Unit 29155.
The four explosions were part of a series of blasts that occurred over the past 10 years, said Siika Mileva, a spokeswoman for the prosecutor general. At least two happened at a time when members of the unit were frequently traveling in and out of Bulgaria, she said, and among the damaged goods was military matériel belonging to Emilian Gebrev, a major Bulgarian arms manufacturer who, officials say, was poisoned in 2015, along with his son and a senior executive at his company, by members of the same Russian unit.
The announcement comes just over a week after authorities in the Czech Republic blamed two similar explosions at ammunition depots in that country in 2014 on operatives from Unit 29155, which specializes in sabotage and assassination. Those depots also contained ammunition owned by Mr. Gebrev’s company, Emco.
“A reasonable assumption can be made about a link between the explosions on Bulgarian territory, the attempts to poison three Bulgarian citizens and serious crimes committed on the territory of foreign countries,” Ms. Mileva said.
Sergei V. Skripal in Britain and an attempted coup in Montenegro two years earlier. Last year, The New York Times revealed a C.I.A. assessment that the group may have carried out a covert effort to pay bounties to militants in Afghanistan for attacks on American and coalition troops.
Mr. Gebrev acknowledged selling ammunition and military equipment to “authorized Ukrainian companies” in late 2014. Though, Mr. Gebrev insists he provided only a small amount of military equipment, it would have offered a lifeline to Ukraine at a time when few Western countries would provide weaponry.