Most are men in their 20s and all are convicted of terrorism. The FSB claims that the individuals were lured with offers of "quick money", which they claim was promised by the Ukrainian intelligence service.
According to the FSB, they "carried out arson attacks on transport infrastructure and volunteer organizations". They are also alleged to have planned attacks on military bases.
On Thursday, Russia's President Vladimir Putin praised secret Russian military courts for handing down over a thousand terror-related sentences last year.
Russia routinely prosecutes citizens accused of collaborating with Ukraine for terror-related crimes.
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