In June 1941, Germany launched Operation Barbarossa, attacking the USSR. Britain and the USSR agreed an alliance the following month with the Anglo-Soviet Agreement and joined the Second Inter-Allied Meeting in London. The USSR thereafter became one of the Allies of World War II along with Britain, fighting against the Axis Powers. The Anglo-Soviet invasion of Iran secured the oil fields in Iran from falling into Axis hands. The Arctic convoys transported supplies between Britain and the USSR during the war. Britain was quick to provide limited material aid to the Soviet Union - including tanks and aircraft - via these convoys in order to try to keep her new ally in the war against Germany and her allies. One major conduit for supplies was through Iran. The two nations agreed on a joint occupation of Iran, to neutralize German influence. After the war, there were disputes about the Soviet delayed departure from Iran, and speculation that it planned to set up a puppet state along its border. That problem was resolved completely in 1946.