(front),
Marian Spychalski and
Michał Rola-Żymierski in the area of the
Lusatian Neisse River after fording it in April 1945 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. In June 1943, the
Union of Polish Patriots (ZPP) was founded in Moscow. The ZPP was a mass-membership, communist-led organization for Polish citizens. It conducted political activities and organized large-scale social welfare and relief programs for Polish communities in the Soviet Union. The ZPP was led by the pro-Soviet
Polish communist Wanda Wasilewska. At the same time, due to the efforts of Wasilewska and
Zygmunt Berling, a new army was established—the
Polish People's Army (
Ludowe Wojsko Polskie, LWP). Its first unit, the
Polish 1st Tadeusz Kościuszko Infantry Division (
1 Dywizja Piechoty im. Tadeusza Kościuszki), was created in the summer of 1943, reaching operational readiness by June/July. In August, the division was enlarged to a corps, becoming the Polish 1st Corps. It was placed under command of General Berling; other notable commanders included General
Karol Świerczewski and Col.
Włodzimierz Sokorski. The division with its supporting elements was sent to the
Eastern Front in September 1943 and its first major engagement was the
Battle of Lenino. By March 1944, the corps had been strengthened with increasing armoured and mechanical support and numbered over 30,000 soldiers. In mid-March 1944, the corps was reorganized into the
First Polish Army. Subsequent Soviet-created Polish army units on the Eastern Front included the
Second (1945) and Third Polish Armies (the latter was quickly merged with the Second due to recruitment problems); the smaller formations included 10 infantry divisions (numbered from 1st to 10th) and 5
armoured brigades. Plans for a Polish Front were considered but dropped, and the Polish First Army was integrated into the
1st Belorussian Front. These formations were led by Soviet commanders and fought under Soviet general command (the Second Army, for example, was led by the Soviet and Polish general
Stanislav Poplavsky). There was a shortage of Polish officers (most were killed at Katyn or departed with Anders' Army) and in the Polish First Army and the Second Army approximately 40% of officers and engineers were Soviet. Special political officers, almost exclusively made up of Soviets, oversaw the Polish soldiers. The Soviets also created political
military police, which later became the
Main Directorate of Information of the Polish Army (Główny Zarząd Informacji Wojska Polskiego). The First Army entered Poland from Soviet territory in the summer of 1944, on the right wing of the
Lvov–Sandomierz Offensive, fighting in the battles during the Soviet crossing of the
Vistula River around
Dęblin and
Puławy. In September 1944, units of the First Army were involved in heavy fighting during the latter stages of the
Warsaw Uprising, after crossing the Vistula following the capture of
Warsaw's eastern
Praga district, but suffered heavy losses. After eventually taking control of Warsaw in January 1945, the First Army took part in the
Vistula–Oder Offensive. Subsequently, it fought in
Pomerania, breaking through the
Pomeranian Wall (
Pommernstellung) fortified line and
capturing Fortress Kolberg, a heavily fortified city, in March. In April–May 1945, the First Army took part in the Soviet invasion of Germany and the final
capture of Berlin. The Second Army reached operational readiness in January 1945. During the Soviet invasion of Germany it suffered very heavy losses at the
Battle of Bautzen. Later it took part in the
Prague Offensive, which was the last major Soviet operation of World War II in
Europe. ==First Polish Army (Berling's Army)==