In 1941 he was given his first overseas assignment in New York as a case officer at the NKVD station (Rezidentura) at the Soviet Consulate general under the alias name of Anatoly Yakovlev.

He was employed as a consular apprentice until 1943, being eventually promoted to Soviet vice-consul (ranking 3rd Secretary).

NKVD New York station was crucial for the Soviet Union in obtaining most sensitive data on the U.S. Army Los Alamos nuclear facility and precise knowledge on development of the A-Bomb.

Being close with the Cohens, Yatskov was able to covertly communicate with chief atomic scientist Klaus Fuchs directly involved in the Manhattan Project.

He was engaged in case handlings in Europe and Asia, in the 1950s being posted to Paris and Berlin as well as covertly living for some time in Iraq as a Canadian national.