In August 1963 the governments of the US and USSR exchanged diplomatic cables discussing the erection of the Berlin Wall:

“The Embassy of the United States presents its compliments to the Minister of Foreign Affairs and upon instructions of its government has the honour to direct the most serious attention of the government of the USSR to the following.

On August 13th East German authorities put into effect several measures regulating movement at the boundary of the western sectors and the Soviet sector of the city of Berlin. These measures have the effect of limiting, to a degree approaching complete prohibition, passage from the Soviet sector to the western sectors of the city. These measures were accompanied by the closing of the sector boundary by a sizeable deployment of police forces and by military detachments brought into Berlin for this purpose.

All this is a flagrant, and particularly serious, violation of the quadri-partite status of Berlin… The United States government has never accepted that limitations can be imposed on freedom of movement within Berlin. The boundary between the Soviet sector and the western sectors of Berlin is not a state frontier. The United States government considers that the measures which the East German authorities have taken are illegal. It reiterates that it does not accept the pretension that the Soviet sector of Berlin forms a part of the so-called “German Democratic Republic” and that Berlin is situated on its territory…

By the very admission of the East German authorities, the measures which have just been taken are motivated by the fact that an ever increasing number of inhabitants of East Germany wish to leave this territory. The reasons for this exodus are known. They are simply the internal difficulties in East Germany…

The United States government solemnly protests against the measures referred to above, for which it holds the Soviet Government responsible. The United States Government expects the Soviet Government to put an end to these illegal measures. This unilateral infringement of the quadripartite status of Berlin can only increase existing tension and dangers.”

US State Department
August 17th 1963

In connection with the note of the government of the United States of America of August 17th 1961, the government of the Union of Soviet Socialist Republics considers it necessary to state the following:

The Soviet government fully understands and supports the actions of the government of the German Democratic Republic (GDR) which established effective control on the border with West Berlin in order to bar the way for subversive activity being carried out from West Berlin against the GDR and other countries of the socialist community…

West Berlin has been transformed into a centre of subversive activity diversion, and espionage, into a centre of political and economic provocations against the GDR, the Soviet Union, and other socialist countries. Former and present West Berlin municipal leaders have cynically called West Berlin an “arrow in the living body of the German Democratic Republic,” a “front city,” a “violator of tranquillity,” the “cheapest atom bomb put in the centre of a socialist state”…

The government of the USA should be well informed on the fact that, with the collaboration of the occupation forces, the ruling circles of the FRG have turned West Berlin into the principal base of uninterrupted economic diversions against the GDR… The government organs and concerns of the FRG led from West Berlin an entire army of recruiters who, by means of deception, bribery, and blackmail, encouraged a certain part of the residents of the GDR to migrate to West Germany…

Slanderous propaganda of incitement, inimical to the Soviet Union, the GDR and other socialist countries, has been and is being systematically conducted by radio and television from West Berlin. The radio and television centres in West Berlin are totally subordinated to one task: to disseminate enmity among peoples, to incite war psychosis, to attempt to organise disorders, and to transmit enciphered instructions to agents of Western intelligence systems…

The GDR has displayed, over the course of many years, great tolerance in the face of such a completely disgraceful and impermissible situation. Implementing its consistently peace-loving and democratic policy, it has borne enormous sacrifices to facilitate the achievement of an agreement between the two German states on the questions of peaceful settlement and reunification of Germany on peace-loving and democratic foundations…

As was already stated, measures taken by the government of the GDR are temporary. The Soviet government has repeatedly emphasised that the conclusion of a peace treaty with Germany and normalisation on such a basis of the situation in West Berlin will not infringe the interests of any of the parties and will contribute to the cause of peace and security of all peoples.”

Soviet Foreign Ministry, Moscow
August 18th 1963