The detainees have already been notified what charges have been brought against them, according to the video.

"The servicemen of the State Border Guard Service of Ukraine who were detained in the Russian Federation on October 3, 2017, for violation of the border with Ukraine as part of a previously opened criminal case under Part 3 of Article 322 of the Criminal Code of the Russian Federation (illegal crossing of the state border of the Russian Federation) have been given notice of formal charges," a post on the FSB's website reads.

Read alsoRussian courts arrests for 2 months Ukrainian border guards earlier gone missing near Russia borderAs UNIAN reported earlier, Ukraine's State Border Guard Service said two servicemen went missing on duty on October 3 while monitoring the border with Russia in Sumy region in Ukraine's north.

Meanwhile, Russian media outlets reported two men who introduced themselves as border guards of the Ukrainian Sumy border guard detachment had been detained by the Russian FSB's border unit allegedly for the illegal crossing of the Ukrainian-Russian border.

Ukraine's prosecutors in Sumy region opened criminal proceedings on the disappearance of two members of the Ukrainian State Border Guard Service.