The Security Service of Ukraine (SBU) had detained five individuals, including former and current officials of Ukraine's intelligence services, allegedly working for the Russian Federal Security Service (FSB) in various regions of Ukraine, the SBU's press service reported on Feb. 6.
The suspects were allegedly tasked with passing intelligence about Ukraine's military and strategically important energy facilities to the FSB. They were managed by an FSB handler based in Russian-occupied Crimea, the SBU said.
"The group included former officials of the Main Intelligence Directorate of the Ministry of Defense (HUR, the military intelligence agency), the Foreign Intelligence Service of Ukraine (SZRU), and a regional SBU department employee," the SBU said.
According to the SBU's statement, the suspects were provided with financial rewards in return for their work. The FSB also used threats to kill the suspects' families to ensure their cooperation, the SBU said.
A former foreign intelligence officer was recruited by the FSB before Russia's full-scale invasion, while he was still working at the intelligence agency, according to the SBU.
"Since then, he has been gathering information about locations of Ukrainian military bases, and after Feb. 24, 2022, about channels for delivering foreign weapons to Ukraine," the statement read.
The suspect also allegedly passed secret information about the security systems at the Rivne and Khmelnytskyi nuclear power plants to the FSB.
"He passed intelligence to the FSB through an accomplice who traveled abroad as a volunteer and personally reported to the FSB handler," the SBU said.
"He passed especially sensitive information on a flash drive via smugglers from border areas of Ukraine."
Another suspected spy, who previously served at the military intelligence agency, allegedly leaked personal data of Ukrainian soldiers.
The last suspect, an SBU employee, scouted locations of fortifications and engineering barriers near the Black Sea coastline, the SBU said.
The suspects had already been detained on the charges of high treason.
This is another major crackdown against Russian espionage networks this week. The SBU announced on Feb. 5 that it had detained five individuals allegedly spying on the Ukrainian military in Odesa, Zaporizhzhia, and Donetsk oblasts and passing information to the FSB.