Photo from UNIAN

"The operatives of the border unit have arrested six citizens of Ukraine who had been conducting surveillance in the area of training of the SSC detachments," the statement of the SSC of Transnistria reads on its website, according to Ukraine Today.

In turn, spokesman of Ukraine's State Border Guard Service Oleh Slobodian told Hromadske Radio that the detainees had not conducted any surveillance.

Read alsoRussia formally charges Ukrainian journo Sushchenko with espionage"Citizen Maliuta has nothing to do with a military service or service with the border guards. He had a time job as a fireman in one of the [Border Guard Service] units,", Slobodian said.

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"They were arrested somewhere near Ukraine's borderline and handed over to Russian military representatives in the Transnistrian part of Moldova as if they were military persons conducting a surveillance," Slobodian added.

The events in Transnistria, a "breakaway" formation separated by the Kremlin from Moldova, were instigated after the declaration of independence by Moldova in 1991. The Russian-speaking part of the Transnistrian population feared the creation of a "nationalistic" Moldovan state seeking ties intensification with its historically close neighbor – Romania. The conflict developed into the Russia-negotiated ceasefire with Moscow sending to Transnistria a contingent of "peacekeepers", which is still based there.

Read alsoUkrainian man sentenced to 14 yrs in prison for spying for RussiaThe conflict is considered unresolved, and occasional negotiations on the crisis are held by Moldova, Ukraine, Russia and the West.