In a Saturday statement, the FSB said it had detained an “agent of the Ukrainian Security Service… sent to Crimea to carry out acts of sabotage.”
The man named, Gennady Lemeshko, was arrested on Saturday while “attempting to damage a power line” and was carrying a grenade, two sticks of TNT and a hand saw, the FSB added.
Russian state television showed footage of the man under interrogation.
According to the statement, Lemeshko was as a former military reconnaissance officer in eastern Ukraine.
Lemeshko ‘s mission was to destroy a power line out of order, to light forest fires, set fire to an administrative building and cause a landslide in an attempt block a highway, the FSB said.
Crimea still relies on Ukraine for its power supply.
A spokesman for the Ukrainian border service Oleg Slobodyan confirmed that a Ukrainian citizen of that name had entered Crimea on August 9.
“He did not have any banned items with him” and Russian officials allowed him into Crimea, Slobodyan said.
The Ukrainian military also confirmed that Lemeshko had served in the armed forces on a contract from November 2016 to May 2017.
However, a Ukrainian Security Service statement rejected the allegations of detention of one of its agents in Crimea as a “provocation” and “fake news.”
In 2015, Ukrainian far-right groups and Crimean Tatars, who opposed Crimea’s annexation to Russia, detonated explosives at high voltage power lines, cutting power supply to over a million Crimean residents.
Conflict erupted in eastern Ukraine following the overthrow of Ukraine’s pro-Russian president Viktor Yanukovych and after people in Crimea voted for unification with Russia in March 2014. The West brands the unification as annexation of the territory by Russia. The US and its allies in Europe also accuse Russia of having a major hand in the crisis in eastern Ukraine, an allegation denied by Moscow.
The crisis has left over 10,000 people dead and more than a million others displaced, according to the United Nations.
The warring sides have signed at least two peace deals since 2014, but fighting has not ended.