Operatives reportedly set fire to a depot in the oblast's Olkhovatsky district, located some 70 kilometers (43 miles) from the border with Ukraine's Luhansk Oblast. The fire resulted in an explosion, the agency said.
Unnamed security officials told the Wall Street Journal that a number of details revealed in the subsequent investigation into the fire point to Russian involvement and the direct work of "experienced professionals."
Three men were arrested in Germany on suspicion of cooperating with a foreign secret service, the German Federal Prosecutor's Office reported on June 21.
"Free movement of holders of Russian diplomatic and service passports, accredited in one host state, across the whole Schengen area is easing malign activities," the letter to EU's foreign policy chief Josep Borrell said.
A Russian woman was arrested in Denmark and charged with helping a foreign intelligence service operate in the country, the Danish national broadcaster DR reported on June 11, citing the Danish Police Intelligence Service (PET).
Czech Prime Minister Petr Fiala said on June 10 that Russia may be linked to an attempted arson attack on Prague city buses last week.
In an apparent reference to increased cases of Russian sabotage across Europe, Poland's Prime Minister Donald Tusk said his government was "very vigilant and sensitive" to such cases for "obvious reasons."
At least one of the suspects was involved in an alleged plot to assassinate Ukraine's President Volodymyr Zelensky, while the other ten were involved in planning various forms of sabotage, such as arson, across Poland.
"We hope that the Russian Federation will treat this as a very serious warning," Polish Foreign Minister Radoslaw Sikorski said.
U.S. and allied intelligence officials have noted a growing number of low-level sabotage operations in Europe that seem to be a part of Russia's effort to undermine assistance for Ukraine, the New York Times (NYT) reported on May 26.
Polish authorities are increasing security at the main transit hub for foreign military aid to Ukraine amidst increased threats of Russian-backed sabotage, Bloomberg reported on May 23.
Estonian Prime Minister Kaja Kallas said she was concerned that some other European leaders have not viewed the uptick in incidents of sabotage and arrest of suspected spies across the EU to be interconnected.
Investigators told France Info that there is "little doubt" it was an "operation to destabilize public opinion from Russia."
The Polish government arrested nine people from a Russian spy ring in connection to alleged sabotage plots, Prime Minister Donald Tusk told Polish media outlet TVN24.
The country's investigators believe that Andrey Averyanov coordinated the supposed Russian sabotage operation in 2014 that led to ammunition depot blasts in the eastern Czech town of Vrbetice, killing two people and causing damages in tens of millions of dollars.
Several high-profile incidents in recent weeks have put a spotlight on cases of attempted sabotage by people accused of working on the Kremlin's behalf.
NATO released a statement condemning Russian "hybrid actions" after multiple individuals were accused of working on behalf of Russia from within NATO territory.
Russian military intelligence operatives were responsible for deadly ammunition depot explosions in Czechia in 2014, the Czech police said on April 29 following a three-year investigation.
Two diesel locomotives have been destroyed in Russia over the past few days, Ukraine's military intelligence (HUR) reported on April 28.
Since the start of Russia's full-scale invasion of Ukraine, what were previously treated as acts of hooliganism have often been tried as acts of sabotage aimed at disrupting the Kremlin's war effort and those found guilty now face far harsher punishments.
"The actions were intended in particular to undermine the military support provided by Germany to Ukraine against the Russian war of aggression," the prosecutors said.
Border guards repelled an attack by Russian saboteurs in Sumy Oblast, Ukraine's State Border Guard Service reported on April 15.
An oil pipeline near the Russian city of Azov, Rostov Oblast, that was funneling oil products to tankers in the Azov Sea Port was blown up overnight on April 6, Ukraine's military intelligence agency (HUR) said.
Czech Transportation Minister Martin Kupka said that Russia has made "thousands of attempts to weaken our (railway) systems" since the beginning of the full-scale war.
Russian forces attacked eight border areas and settlements of Sumy Oblast on April 1, firing 22 times and causing at least 113 explosions, the Sumy Oblast Military Administration reported.
Border guards repelled an attack by Russian saboteurs in Sumy Oblast, Ukraine's State Border Guard Service reported on April 1.
The Prosecutor General's Office added that the two suspects were Ukrainian citizens.
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