The Ukrainian Security Service (SBU) says it has detained a Russian man on suspicion of preparing an act of sabotage at a "strategically important military site."
The man, who was not identified, was detained at his residence in the central Ukrainian city of Cherkasy, according to a statement on August 8.
It said the suspect was in possession of three homemade explosive devices, 2 kilograms of chemicals, an electronic detonator, two types of explosives, notes with chemical formulas, and explosives-making literature.
The statement said he had gathered intelligence at a military airfield and was found to have materials that prove he had been collecting information about the facility.
It didn't specify which military site the Russian was allegedly targeting.
The man, who is now in pretrial detention, faces charges of conducting subversive activity and illegally handling weapons, ammunition, and explosives.
If found guilty, he faces between eight and 15 years in prison for the greater charge of subversion.