Viktor Cherkesov, a longtime associate of Russian President Vladimir Putin who fell foul of the Kremlin for publicly discussing a rift within Russia’s security elites, has died in St. Petersburg at age 72. Cherkesov’s death, which followed “a severe illness,” was announced late Tuesday by the Rosbalt news website. He is survived by his wife, Natalia Cherkesova. Cherkesov began his KGB career in 1975, the same year as Putin joined the agency. After rising in the ranks, he continued to work for KGB’s successor, the Federal Security Service (FSB), after the collapse of the Soviet Union and served…