the closest i can find to any relation of tesla to the ussr is him making a business deal through a front company to sell schematics to the soviet government in 1935.  assuming the quote is real then it at the absolute earliest would be in the mid 1920s, but its far more likely to be in the latter 30s to maybe the early 40s. tesla died in 43 so assuming the quote is close to that time it would have been when the us was specifically trying to put a happy face on the soviets and improve relations with them
United States