When did Hitler issue the directive to prepare to invade the Soviet Union ?
In an unannounced November 25 visit in Sofia , the Soviets told the Bulgarian Prime Minister that , if Bulgaria permitted the Soviets troop transfer access , the Soviets were prepared to drop their objections to Bulgaria 's entry into the Axis and , most surprisingly , stated that it likely would not be an issue as it would " very probably , almost certainly " lead to the Soviets ' own entry into the Axis .