In the context of the Russo-Ukrainian War, in the time leading up to and after the 2022 Russian invasion of Ukraine, a number of citizens of the Russian Federation and of other nationalities working for Russia have been identified publicly as spies or agents of the Federal Security Service (FSB), the Russia's foreign intelligence service (SVR) or the third intelligence arm, the military intelligence service (GRU). Each arm having their own remits.[1][2]
Termed "illegals", operatives without diplomatic accreditation, agents often spend years building up false identities, living a quiet life, though sometimes they then move location/country with their partner, who may or may not know of their espionage activities and any children, who will not know of any nefarious activities. They can be hard to identify, resembling normal people.[2]
The threat of spies has been increasing in Europe, most of which are Russian.[3] "Counterintelligence efforts to look for illegals had intensified recently".“The breadth of Moscow’s spying operations made it a unique threat", said Janez Stušek, director of Slovenia's SOVA intelligence agency until June 2022.[4]
guard243 was invoked but never defined (see the help page).