Immediately after Nazi Germany’s attack on the U.S.S.R., representatives of Great Britain and the United States voiced their support of the Soviet Union and started providing economic assistance to it.
On July 12, 1941, the U.S.S.R. and Britain signed an agreement on joint actions in the war against Germany. The U.S.S.R. and the United States then also concluded an agreement on the principles of mutual assistance in the war against aggression.
In October 1941, Moscow hosted a joint conference of representatives from the U.S.S.R., the United States and Great Britain that coordinated the organization of reciprocal military supplies to better use material resources in the war against Nazi Germany.
After the United States and China joined the war, on January 1, 1942, representatives of the U.S.S.R., the United States, Britain and China signed a Declaration by United Nations in Washington laying the foundation of a large international coalition of democratic countries later joined by another 22 countries.
The Declaration contained the countries’ commitment to use all military and economic resources they had to fight Nazi states, as well as the commitment not to conclude a separate peace treaty with them. From that moment, it came to be considered that the Nazi bloc states wage war not against separate countries but against the United Nations.
The Allied states’ commitments were consolidated at the Tehran conference in November-December 1943, and at the Yalta conference in February 1945. Cooperation between the anti-Hitler coalition countries became the basis of the United Nations Organization.