The Warsaw Uprising (Polish: powstanie warszawskie; German: Warschauer Aufstand) was a major World War II operation, in the summer of 1944, by the Polish underground resistance, led by the Polish resistance Home Army (Polish: Armia Krajowa), to liberate Warsaw from German occupation. The uprising was timed to coincide with the retreat of the German forces from Poland ahead of the Soviet advance. While approaching the eastern suburbs of the city, the Red Army temporarily halted combat operations, enabling the Germans to regroup and defeat the Polish resistance and to destroy the city in retaliation. The Uprising was fought for 63 days with little outside support. It was the single largest military effort taken by any European resistance movement during World War II.
The Uprising began on 1 August 1944 as part of a nationwide Operation Tempest, launched at the time of the Soviet Lublin–Brest Offensive. The main Polish objectives were to drive the Germans out of Warsaw while helping the Allies defeat Germany. An additional, political goal of the Polish Underground State was to liberate Poland’s capital and assert Polish sovereignty before the Soviet-backed Polish Committee of National Liberation could assume control. Other immediate causes included a threat of mass German round-ups of able-bodied Poles for „evacuation”; calls by Radio Moscow’s Polish Service for uprising; and an emotional Polish desire for justice and revenge against the enemy after five years of German occupation.
Initially, the Poles established control over most of central Warsaw, but the Soviets ignored Polish attempts to make radio contact with them and did not advance beyond the city limits. Intense street fighting between the Germans and Poles continued. By 14 September, the eastern bank of the Vistula River opposite the Polish resistance positions was taken over by the Polish troops fighting under the Soviet command; 1,200 men made it across the river, but they were not reinforced by the Red Army. This, and the lack of air support from the Soviet air base five-minutes flying time away, led to allegations that Joseph Stalin tactically halted his forces to let the operation fail and allow the Polish resistance to be crushed. Arthur Koestler called the Soviet attitude „one of the major infamies of this war which will rank for the future historian on the same ethical level with Lidice.”
Winston Churchill pleaded with Stalin and Franklin D. Roosevelt to help Britain’s Polish allies, to no avail. Then, without Soviet air clearance, Churchill sent over 200 low-level supply drops by the Royal Air Force, the South African Air Force, and the Polish Air Force under British High Command, in an operation known as the Warsaw Airlift. Later, after gaining Soviet air clearance, the U.S. Army Air Force sent one high-level mass airdrop as part of Operation Frantic.
Although the exact number of casualties is unknown, it is estimated that about 16,000 members of the Polish resistance were killed and about 6,000 badly wounded. In addition, between 150,000 and 200,000 Polish civilians died, mostly from mass executions. Jews being harboured by Poles were exposed by German house-to-house clearances and mass evictions of entire neighbourhoods. German casualties totalled over 2,000 to 17,000 soldiers killed and missing. During the urban combat, approximately 25% of Warsaw’s buildings were destroyed. Following the surrender of Polish forces, German troops systematically levelled another 35% of the city block by block. Together with earlier damage suffered in the 1939 invasion of Poland and the Warsaw Ghetto Uprising in 1943, over 85% of the city was destroyed by January 1945 when the course of the events in the Eastern Front forced the Germans to abandon the city.
In 1944, Poland had been occupied by Nazi Germany for almost five years. The Polish Home Army planned some form of rebellion against German forces. Germany was fighting a coalition of Allied powers, led by the Soviet Union, the United Kingdom and the United States. The initial plan of the Home Army was to link up with the invading forces of the Western Allies as they liberated Europe from the Nazis. However, when the Soviet Army began its offensive in 1943, it became clear that Poland would be liberated by it instead of the Western Allies.
In this country, we have one point from which every evil emanates. That point is Warsaw. If we didn’t have Warsaw in the General Government, we wouldn’t have four-fifths of the difficulties with which we must contend. — German Governor-General Hans Frank, Kraków, 14 December 1943 
The Soviets and the Poles had a common enemy—Germany—but were working towards different post-war goals: the Home Army desired a pro-Western, capitalist Poland, but the Soviet leader Stalin intended to establish a pro-Soviet, socialist Poland. It became obvious that the advancing Soviet Red Army might not come to Poland as an ally but rather only as „the ally of an ally”.
„The Home Commander was, in his political thinking, pledged to the doctrine of two enemies, in accordance with which both Germany and Russia were seen as Poland’s traditional enemies, and it was expected that support for Poland, if any, would come from the West”.Warsaw Old Town in flames during Warsaw Uprising
The Soviets and the Poles distrusted each other and Soviet partisans in Poland often clashed with a Polish resistance increasingly united under the Home Army’s front. Stalin broke off Polish–Soviet relations on 25 April 1943 after the Germans revealed the Katyn massacre of Polish army officers, and Stalin refused to admit to ordering the killings and denounced the claims as German propaganda. Afterwards, Stalin created the Rudenko Commission, whose goal was to blame the Germans for the war crime at all costs. The Western alliance accepted Stalin’s words as truth in order to keep the Anti-Nazi alliance intact. On 26 October, the Polish government-in-exile issued instructions to the effect that, if diplomatic relations with the Soviet Union were not resumed before the Soviet entry into Poland, Home Army forces were to remain underground pending further decisions.
However, the Home Army commander, Tadeusz Bór-Komorowski, took a different approach, and on 20 November, he outlined his own plan, which became known as Operation Tempest. On the approach of the Eastern Front, local units of the Home Army were to harass the German Wehrmacht in the rear and co-operate with incoming Soviet units as much as possible. Although doubts existed about the military necessity of a major uprising, planning continued. General Bór-Komorowski and his civilian advisor were authorised by the government in exile to proclaim a general uprising whenever they saw fit.
The situation came to a head on 13 July 1944 as the Soviet offensive crossed the old Polish border. At this point the Poles had to make a decision: either initiate the uprising in the current difficult political situation and risk a lack of Soviet support, or fail to rebel and face Soviet propaganda describing the Home Army as impotent or worse, Nazi collaborators. They feared that if Poland was liberated by the Red Army, then the Allies would ignore the London-based Polish government in the aftermath of the war. The urgency for a final decision on strategy increased as it became clear that, after successful Polish-Soviet co-operation in the liberation of Polish territory (for example, in Operation Ostra Brama), Soviet security forces behind the frontline shot or arrested Polish officers and forcibly conscripted lower ranks into the Soviet-controlled forces. On 21 July, the High Command of the Home Army decided that the time to launch Operation Tempest in Warsaw was imminent. The plan was intended both as a political manifestation of Polish sovereignty and as a direct operation against the German occupiers. On 25 July, the Polish government-in-exile (without the knowledge and against the wishes of Polish Commander-in-Chief General Kazimierz Sosnkowski) approved the plan for an uprising in Warsaw with the timing to be decided locally.
In the early summer of 1944, German plans required Warsaw to serve as the defensive centre of the area and to be held at all costs. The Germans had fortifications constructed and built up their forces in the area. This process slowed after the failed 20 July plot to assassinate the Nazi leader Adolf Hitler, and around that time, the Germans in Warsaw were weak and visibly demoralized. However, by the end of July, German forces in the area were reinforced. On 27 July, the Governor of the Warsaw District, Ludwig Fischer, called for 100,000 Polish men and women to report for work as part of a plan which envisaged the Poles constructing fortifications around the city. The inhabitants of Warsaw ignored his demand, and the Home Army command became worried about possible reprisals or mass round-ups, which would disable their ability to mobilize. The Soviet forces were approaching Warsaw, and Soviet-controlled radio stations called for the Polish people to rise in arms.
On 25 July, the Union of Polish Patriots, in a broadcast from Moscow, stated:
„The Polish Army of Polish Patriots … calls on the thousands of brothers thirsting to fight, to smash the foe before he can recover from his defeat … Every Polish homestead must become a stronghold in the struggle against the invaders … Not a moment is to be lost.”
On 29 July, the first Soviet armoured units reached the outskirts of Warsaw, where they were counter-attacked by two German Panzer Corps: the 39th and 4th SS. On 29 July 1944 Radio Station Kosciuszko located in Moscow emitted a few times its „Appeal to Warsaw” and called to „Fight The Germans!”:
„No doubt Warsaw already hears the guns of the battle which is soon to bring her liberation. … The Polish Army now entering Polish territory, trained in the Soviet Union, is now joined to the People’s Army to form the Corps of the Polish Armed Forces, the armed arm of our nation in its struggle for independence. Its ranks will be joined tomorrow by the sons of Warsaw. They will all together, with the Allied Army pursue the enemy westwards, wipe out the Hitlerite vermin from Polish land and strike a mortal blow at the beast of Prussian Imperialism.”
Bór-Komorowski and several officers held a meeting on that day. Jan Nowak-Jeziorański, who had arrived from London, expressed the view that help from the Allies would be limited, but his views received no attention.
„In the early afternoon of 31 July the most important political and military leaders of the resistance had no intention of sending their troops into battle on 1 August. Even so, another late afternoon briefing of Bor-Komorowski’s Staff was arranged for five o’clock(…) At about 5.30 p.m. Col 'Monter’ arrived at the briefing, reporting that the Russian tanks were already entering Praga and insisting on the immediate launching of the Home Army operations inside the city as otherwise it 'might be too late’. Prompted by 'Monter`s report, Bor-Komorowski decided that the time was ripe for the commencement of 'Burza’ in Warsaw, in spite of his earlier conviction to the contrary, twice expressed during the course of that day”.
„Bor-Komorowski and Jankowski issued their final order for the insurrection when it was erroneously reported to them that the Soviet tanks were entering Praga. Hence they assumed that the Russo-German battle for Warsaw was approaching its climax and that this presented them with an excellent opportunity to capture Warsaw before the Red Army entered the capital. The Soviet radio appeals calling upon the people of Warsaw to rise against the Germans, regardless of Moscow’s intentions, had very little influence on the Polish authorities responsible for the insurrection”.
Believing that the time for action had arrived, on 31 July, the Polish commanders General Bór-Komorowski and Colonel Antoni Chruściel ordered full mobilization of the forces for 17:00 the following day.
Within the framework of the entire enemy intelligence operations directed against Germany, the intelligence service of the Polish resistance movement assumed major significance. The scope and importance of the operations of the Polish resistance movement, which was ramified down to the smallest splinter group and brilliantly organized, have been in (various sources) disclosed in connection with carrying out of major police security operations.— Heinrich Himmler, 31 December 1942