"The Russian Federal Security Service on the territory of the Samara Region has uncovered and suppressed the illegal activities of two agents of Ukrainian special services, Russian citizens..." the statement said, adding that one of Ukraine's agents blew up a transformer substation of the Kuibyshev oil refinery in the Samara Region.
The second detainee was involved in preparing sabotage using homemade bombs at defense industry facilities on Kiev's instructions, the FSB said.
The Ukrainian special services recruit and prepare agents in Moldova to be sent to Russia to commit terrorist attacks, the statement added.