MOSCOW, December 23. /TASS/. The Federal Security Service (FSB) has detained six Russian citizens caught spying for Ukraine’s Security Service and military in a number of Russian regions, the FSB reported on Friday.

"The FSB foiled the criminal activity of Russian and Ukrainian nationals who have been cooperating with the Security Service and the Armed Forces of Ukraine" in the Perm Region, the Jewish Autonomous Region and the Rostov Region, the FSB said in a report.

The FSB’s Investigative Department has opened criminal cases against those individuals.

In the Perm Region, a group of agents spying for the Ukrainian Security Service included three Russian citizens tasked with plotting and conducting terror attacks and sabotage on key public and infrastructure facilities in Perm near the Urals. They also assisted Ukraine’s intelligence in undermining the social and political situation in the region, the FSB specified.

In the Jewish Autonomous Region, a 35-year-old was detained on suspicion of treason for Ukrainian intelligence. He had been gathering information about key local infrastructure and forwarding that to a Ukrainian intelligence officer.

In the Rostov Region, the FSB nabbed a resident of the Volgograd Region who was planning to cross the Russian border and join the Ukrainian Army to fight against the Russian Federation. Another Russian national who also holds a Ukrainian passport was found to have transmitted data on the deployment of Russian servicemen and the movement of military hardware to Ukraine in the same region. The coordinates he had obtained were used by Ukrainian forces to deliver a HIMARS rocket strike.

Searches and the investigation continue, the FSB added.