After Anders ' Army left Soviet controlled territory , the Soviet-Polish relations deteriorated and the Soviets decided to assume much greater control over the remaining Polish military potential in the USSR . Activities of organisations and people loyal to the Polish government-in-exile , particularly the Polish embassy in Moscow , were curtailed and its assets confiscated . Diplomatic relations between the Soviet Union and the Polish government were suspended by the Soviet side as news of the Katyn massacre emerged in 1943
Katyn massacre
Katyn massacre
Polish Armed Forces in the East