Finalised in September 1971 during the period of Detente, the Four Powers Agreement on Berlin was signed by the United States, the Soviet Union, Great Britain and France. It reestablished travel and communications between East and West Berlin, and contributed to the easing of tensions between the Western and Soviet blocs:
“Part I: General Provisions
1. The four governments will strive to promote the elimination of tension and the prevention of complications in the relevant area.
2. The four governments, taking into account their obligations under the Charter of the United Nations, agree that there shall be no use or threat of force in the area and that disputes shall be settled solely by peaceful means.
3. The four governments will mutually respect their individual and joint rights and responsibilities, which remain unchanged.
4. The four governments agree that irrespective of the differences in legal views, the situation which has developed in the area, and as it is defined in this Agreement as well as in the other agreements referred to in this Agreement, shall not be changed unilaterally.”
Part II: Provisions Relating to the Western Sectors of Berlin
The government of the Union of Soviet Socialist Republics declares that transit traffic by road, rail and waterways through the territory of the German Democratic Republic of civilian persons and goods between the Western sectors of Berlin and the Federal Republic of Germany will be unimpeded; that such traffic will be facilitated so as to take place in the most simple and expeditious manner; and that it will receive preferential treatment…
The governments of the French Republic, the United Kingdom and the United States of America declare that the ties between the Western Sectors of Berlin and the Federal Republic of Germany will be maintained and developed, taking into account that these Sectors continue not to be a constituent part of the Federal Republic of Germany and not to be governed by it…
The government of the Union of Soviet Socialist Republics declares that communications between the Western Sectors of Berlin and areas bordering on these Sectors and those areas of the German Democratic Republic which do not border on these Sectors will be improved. Permanent residents of the Western Sectors of Berlin will be able to travel to and visit such areas for compassionate, family, religious, cultural or commercial reasons, or as tourists, under conditions comparable to those applying to other persons entering these areas. The problems of the small enclaves, including Steinstuecken, and of other small areas may be solved by exchange of territory. Detailed arrangements concerning travel, communications and the exchange of territory… will be agreed by the competent German authorities…”