The Black Madonna 22: GRU
Glavnoye Razvedyvatel'noye Upravleniye, GRU, the Main Intelligence Directorate is Russia's most powerful intelligence agency. It deploys large numbers of agents across the world and also commands the Spetsnaz GRU, Russia's elite forces.
According to a GRU defector, the organization have completely infiltrated the United States; to the extent that there are arms caches and miniaturized tactical nukes, suitcase bombs, lying in wait for the inevitable confrontation. GRU assassination teams would use these weapons to take out the US leadership during the first days of the war.