«Եթե Նիկոլը և Աննան որոշել են նման քաղաքականություն վարել Հայաստանում, չորս երեխայի տեր են, թող մեկին զոհաբերեն, մենք տեսնենք» (տեսանյութ)

On 22 June 1941, Germany, supported by Italy and Romania, invaded the Soviet Union in Operation Barbarossa, with Germany accusing the Soviets of plotting against them. They were joined shortly by Finland and Hungary.[128] The primary targets of this surprise offensive[129] were the Baltic region, Moscow and Ukraine, with the ultimate goal of ending the 1941 campaign near the Arkhangelsk-Astrakhan line, from the Caspian to the White Seas. Hitler’s objectives were to eliminate the Soviet Union as a military power, exterminate Communism, generate Lebensraum («living space»)[130] by dispossessing the native population[131] and guarantee access to the strategic resources needed to defeat Germany’s remaining rivals.[132]

Although the Red Army was preparing for strategic counter-offensives before the war,[133] Barbarossa forced the Soviet supreme command to adopt a strategic defence. During the summer, the Axis made significant gains into Soviet territory, inflicting immense losses in both personnel and materiel. By the middle of August, however, the German Army High Command decided to suspend the offensive of a considerably depleted Army Group Centre, and to divert the 2nd Panzer Group to reinforce troops advancing towards central Ukraine and Leningrad.[134] The Kiev offensive was overwhelmingly successful, resulting in encirclement and elimination of four Soviet armies, and made possible further advance into Crimea and industrially developed Eastern Ukraine (the First Battle of Kharkov).[135]

Soviet civilians leaving destroyed houses after a German bombardment during the Battle of Leningrad, 10 December 1942
The diversion of three quarters of the Axis troops and the majority of their air forces from France and the central Mediterranean to the Eastern Front[136] prompted the United Kingdom to reconsider its grand strategy.[137] In July, the UK and the Soviet Union formed a military alliance against Germany[138] The British and Soviets invaded neutral Iran to secure the Persian Corridor and Iran’s oil fields.[139] In August, the United Kingdom and the United States jointly issued the Atlantic Charter.[140]

By October Axis operational objectives in Ukraine and the Baltic region were achieved, with only the sieges of Leningrad[141] and Sevastopol continuing.[142] A major offensive against Moscow was renewed; after two months of fierce battles in increasingly harsh weather the German army almost reached the outer suburbs of Moscow, where the exhausted troops[143] were forced to suspend their offensive.[144] Large territorial gains were made by Axis forces, but their campaign had failed to achieve its main objectives: two key cities remained in Soviet hands, the Soviet capability to resist was not broken, and the Soviet Union retained a considerable part of its military potential. The blitzkrieg phase of the war in Europe had ended.[145]

By early December, freshly mobilised reserves[146] allowed the Soviets to achieve numerical parity with Axis troops.[147] This, as well as intelligence data which established that a minimal number of Soviet troops in the East would be sufficient to deter any attack by the Japanese Kwantung Army,[148] allowed the Soviets to begin a massive counter-offensive that started on 5 December all along the front and pushed German troops 100–250 kilometres (62–155 mi) west.[149]

War breaks out in the Pacific (1941)
Main article: Pacific War
In 1939, the United States had renounced its trade treaty with Japan, and beginning with an aviation gasoline ban in July 1940, Japan became subject to increasing economic pressure.[103] During this time, Japan launched its first attack against Changsha, a strategically important Chinese city, but was repulsed by late September.[150] Despite several offensives by both sides, the war between China and Japan was stalemated by 1940. To increase pressure on China by blocking supply routes, and to better position Japanese forces in the event of a war with the Western powers, Japan invaded and occupied northern Indochina.[151] Afterwards, the United States embargoed iron, steel and mechanical parts against Japan.[152]