Development of the inner German border The development of the inner German border took place in a number of stages between 1945 and the mid - 1980s . After its establishment in 1945 as the dividing line between the Western and Soviet occupation zones of Germany , in 1949 the inner German border became the frontier between the Federal Republic of Germany ( FRG , West Germany ) and the German Democratic Republic ( GDR , East Germany ) . The border remained relatively easy to cross until it was abruptly closed by the GDR in 1952 in response to the large - scale emigration of East Germans to the West . Barbed - wire fences and minefields were installed and draconian restrictions were placed on East German citizens living near the border . Thousands were expelled from their homes , with several thousand more fleeing to the West . From the late 1960s , the border fortifications were greatly strengthened through the installation of new fences , detectors , watchtowers and booby - traps designed to prevent attempts to escape from East Germany . The improved border defences succeeded in reducing the scale of unauthorised emigration to a trickle . Origins . The inner German border owed its origins to the agreements reached at the Tehran Conference in November – December 1943 . The conference established the European Advisory Commission ( EAC ) to outline proposals for the partition of a defeated Germany into British , American and Soviet occupation zones ( a French occupation zone was established later ) . At the time , Germany was divided into the series of " gaue " – Nazi administrative subdivisions – that had succeeded the administrative divisions of Weimar Germany . The demarcation line was based on a British proposal of 15 January 1944 . It envisaged a line of control along the borders of the old states or provinces of Mecklenburg , Saxony , Anhalt and Thuringia , which had ceased to exist as separate entities when the Prussia ns unified Germany in 1871 ; minor adjustments were made for practical reasons . The British would occupy the north - west of Germany , the United States the south , and the Soviet Union the east . Berlin was to be a separate joint zone of occupation deep inside the Soviet zone . The rationale was to give the Soviets a powerful incentive to see the war through to the end . It would give the British an occupation zone that was physically close to the UK and on the coast , making it easier to resupply it from the UK . It was also hoped that the old domination of Prussia would be undermined . The United States envisaged a very different division of Germany , with a large American zone in the north , a smaller zone for the Soviets in the east ( the American and Soviet zones meeting at Berlin ) and a smaller zone for the British in the south . President Franklin D . Roosevelt disliked the idea of a U . S . occupation zone in the south , because its supply routes would depend on access through France , which it was feared would be unstable following its liberation . To forestall anticipated American objections , the British proposal was presented directly to the EAC without the prior agreement of the Americans . The Russians immediately accepted the proposal and left the U . S . with little choice but to accept it . The final division of Germany was thus mainly along the lines of the British proposal , with the Americans given the North Sea port - cities of Bremen and Bremerhaven as an enclave within the British zone to ease President Roosevelt ' s concerns about supply routes . The division of Germany came into effect on 1 July 1945 . Because of the unexpectedly rapid Allied advance in central Germany in the final weeks of the war , British and American troops occupied large areas of territory that had been assigned to the Soviet occupation zone . This included a broad area of what was to become the western parts of East Germany , as well as parts of Czechoslovakia and Austria . The redeployment of Western troops at the start of July 1945 was an unpleasant surprise for many German refugees , who had fled west to escape the Russian advance . A fresh wave of refugees headed further west as the Americans and British withdrew and Soviet troops entered the areas allocated to the Soviet occupation zone . Following Germany ' s unconditional surrender in May 1945 , the Allied Control Council ( ACC ) was formed under the terms of the " Declaration on the Defeat of Germany " , signed in Berlin on 5 June 1945 . The council was " the highest authority for matters concerning the whole of Germany " , on which the four powers – France , the UK , the U . S . , and the USSR – were each represented by their supreme commander in Germany . The council functioned from 30 August 1945 until it was suspended on 20 March 1948 , when cooperation between the Western Allies and the Soviets had broken down completely over the issue of Germany ' s political and economic future . In May 1949 , the three western occupation zones were merged to form the Federal Republic of Germany ( FRG ) , a democratically governed federal state with a market economy . The Soviets responded in October 1949 with the establishment of the German Democratic Republic ( GDR ) , a highly centralised communist dictatorship organised along Stalinist lines . The former demarcation lines between the western and eastern zones had now become a " de facto " international frontier – the inner German border . From the outset , West Germany did not accept the legitimacy of the East German state , and for many years regarded the East German government as an illegal organisation intent on depriving Germans of their constitutional rights . It had not been freely or fairly elected , and the creation of East Germany itself was a " fait accompli " by the East German Communists and their Soviet allies . This had important consequences for the inner German border . West Germany regarded German citizenship and rights as unitary , applying equally to East and West German citizens alike . An East German who escaped or was released to the West automatically entered into full enjoyment of those rights , including West German citizenship and social benefits . A would - be immigrant from another country who could get to East Germany could not be barred from entering West Germany across the internal border , which had great significance in later decades . West German laws were deemed to be applicable in the East ; violations of human rights in East Germany could be prosecuted in the West . East Germans thus had a powerful incentive to move to the West , where they would enjoy greater freedom and economic prospects . By contrast , the East German government defined the country as a legitimate state in its own right , not merely the " Soviet occupation zone " ( " sowjetische Besatzungszone " ) as West Germany referred to it . In the terminology of the GDR ' s rulers , West Germany was enemy territory ( " feindliches Ausland " ) . It was portrayed as a capitalist , semi - fascist state that exploited its citizens , sought to regain the lost territories of the Third Reich , and stood opposed to the peaceful socialism of the GDR . 1945 – 52 : the " Green Border " . In the early days of the occupation , the Allies maintained controls on the traffic between the zones within Germany as well as movements over Germany ' s international frontiers . The aim was to manage the flow of refugees and prevent the escape of former Nazi officials and intelligence officers . Travel restrictions in the western zones were gradually lifted as the western German economy improved . In the Soviet zone , however , the poverty and lack of personal freedom led to significant westward emigration . Between October 1945 and June 1946 , 1 . 6 million Germans left the Soviet zone for the west . In response , the Soviets persuaded the Allied Control Council to close all zonal borders on 30 June 1946 and introduce a system of interzonal passes . The interzonal and international borders were initially controlled directly by the Allies . The situation was initially somewhat anarchic immediately after the war , with large numbers of refugees still in transit . On a number of occasions , Soviet and American troops mounted unauthorised expeditions into each other ' s zones to loot and kidnap , and there were incidents of unauthorised shooting across the demarcation line . It became apparent that the Allies by themselves could not effectively seal off the borders and interzonal boundaries . From the first quarter of 1946 , newly trained German police forces under the control of the individual German states took on the task of patrolling the borders alongside Allied troops . ( The pre - war " Grenzpolizei " ( German national border police service ) had been abolished because of its wartime takeover by the Nazis and infiltration by the SS . ) The east – west interzonal border became steadily more tense as the relationship between the Western Allies and the Soviets broke down . From September 1947 an increasingly strict control regime was imposed on the eastern boundary . The number of Soviet soldiers on the boundary was increased and supplemented with border guards from the newly established East German " Volkspolizei " ( " People ' s Police " ) . The West Germans also stepped up border security with the establishment in 1952 of the " Bundesgrenzschutz " or BGS ( Federal Border Guard ) , of 20 , 000 men . Allied troops ( the British in the north , the Americans in the south ) retained responsibility for the military security of the border . The boundary line was nonetheless still fairly easy to cross . Local inhabitants could cross to maintain fields on the other side , or even to live on one side and work on the other . Those who were unable to obtain passes could usually bribe the border guards or sneak across . Refugees from the east , many of them Germans expelled from other countries in central and eastern Europe , were guided across the boundary by villagers in exchange for hefty fees . Other locals on both sides smuggled goods across to supplement their meagre incomes . The number of border migrants remained high despite the increase in East German security measures ; 675 , 000 people fled to West Germany between 1949 and 1952 . There were major differences between how the Western and Eastern sides tackled illegal border crossings . Until the GDR officially acknowledged the inner German border as a " state border " , those who were caught trying to cross it illegally could not be punished under passport control legislation ; instead they were punished for crimes against the economy , principally sabotage . The Western side did not attempt to punish unauthorised crossings by civilians . 1952 – 67 : the " Special Regime " . The border remained largely unfortified for several years after the East and West German republics were established in 1949 , although by this time the GDR had already blocked many unofficial crossing points with ditches and barricades . This changed abruptly on 26 May 1952 when the GDR implemented a " special regime on the demarcation line " , justified as a measure to keep out " spies , diversionists , terrorists and smugglers " . In reality , though , the decision to fortify was taken because the GDR was haemorrhaging citizens at the rate of 10 , 000 – 20 , 000 a month , many of them from the skilled , educated and professional classes . The exodus threatened the viability of East Germany ' s already beleaguered economy . This was also of concern to the Soviets , who proposed a system of passes for visits of West Berlin residents to the territory of East Berlin and advised the East Germans to significantly improve their border defences . The introduction of the " special regime " was carried out as abruptly as the construction of the Berlin Wall nine years later . A ploughed strip 10 m ( 32 . 8 ft ) wide was created along the entire length of the inner German border . An adjoining " protective strip " ( " Schutzstreifen " ) 500 m ( 1 , 640 ft ) wide was placed under severe restrictions . A " restricted zone " ( " " ) a further wide was created in which only those holding a special permit could live or work . Trees and brush were cut down along the border to clear lines of sight for the border guards and eliminate cover for would - be border crossers . Houses adjoining the border were torn down , bridges were closed and barbed - wire fencing was put up in many places . Tight restrictions were placed on farmers , who were permitted to work their fields along the border only in daylight hours and under the watch of armed border guards . The guards were authorised to use " weapons . . . in case of failure to observe the orders of border patrols " . The sudden closure of the border caused acute disruption for communities on both sides . Because the border had previously been merely an administrative boundary , homes , businesses , industrial sites and municipal amenities had been constructed straddling it , and some were now literally split down the middle . In Oebisfelde , residents could no longer access the shallow end of their swimming pool ; in Buddenstedt , the border ran just behind the goal posts of a football field , putting the goalkeeper at risk of being shot by the border guards . An open - cast coal mine at Schöningen was split in half , causing Western and Eastern engineers to race to cart away equipment before the other side could seize it . Workers on both sides found themselves cut off from their homes and jobs . Farmers with land on the other side of the border effectively lost it , as they could no longer reach it . In Philippsthal , a house containing a printing shop was split in two by the border , which ran through the middle of the building . The doors leading to the East German portion of the building were bricked up and blocked until 1976 . The disruption on the eastern side of the border was far worse . Some 8 , 369 civilians living in the " Sperrgebiet " were forcibly resettled in the GDR interior in a programme codenamed " Operation Vermin " ( " " ) . Those expelled from the border region included foreigners and those who had a criminal record , had failed to register with the police or " who because of their position in or toward society pose [ d ] a threat " . Another 3 , 000 residents , realising that they were about to be expelled from their homes , fled to the West . By the end of 1952 , the inner German border was virtually sealed . The border between East and West Berlin was also significantly tightened , although it was not fully closed at this stage . By the end of September 1952 , about 200 of the 277 streets which ran from the Western sectors to the East were closed to traffic and the remainder were subjected to constant police observation . Railway traffic was routed around the Western sectors and all employees of nationalised factories had to pledge not to visit West Berlin on pain of dismissal . However , even with these restrictions the border in Berlin remained considerably easier to cross than the main inner German border ; consequently , Berlin became the main route by which East Germans left for the West . The outflow of people remained considerable despite the new restrictions . Between 1949 and the building of the Berlin Wall in 1961 , an estimated 3 . 5 million East Germans – a sixth of East Germany ' s entire population – emigrated to the West . Events such as the crushing of the 1953 uprising and the shortages caused by the introduction of collectivisation resulted in major increases in refugee numbers . In August 1961 , the Berlin Wall was built , finally putting an end to the stream of refugees . A further expansion of the border regime in July 1962 made the GDR ' s entire Baltic coast a border zone . A wide strip on the eastern side of the Bay of Mecklenburg was added to the tightly controlled protective strip , while restrictions were imposed on coastal activities that might have been useful to would - be escapees . The use of boats at night was curtailed and they were required to moor only in designated areas . Camping and visitor accommodation in the coastal zone required official permission , and residents of the coastal zone required special passes to live there . 1967 – 89 : the " Modern Frontier " . Towards the end of the 1960s , the GDR decided to upgrade the border to establish what East German leader Walter Ulbricht termed the " modern frontier " ( " die moderne Grenze " ) . The redeveloped border system took advantage of the knowledge that had been obtained in building and maintaining the Berlin Wall : the border defences were systematically upgraded to make it far harder to cross ; barbed - wire fences were replaced with harder - to - climb steel mesh ; directional anti - personnel mines and anti - vehicle ditches were introduced to block the movement of people and vehicles ; tripwires and electric signals were introduced to make it easier for the border guards to detect escapees ; all - weather patrol roads were built to enable rapid access to any point along the border ; and wooden guard towers were replaced with prefabricated concrete towers and observation bunkers . Construction of the new border system started in September 1967 . The first phase , from 1967 to 1972 , was initially seen as a strengthening of weak points in the existing system ; subsequently , it became a general rolling programme of work along the entire length of the border . Nearly of new fencing was built , usually further back from the geographical border line than the old barbed - wire fences had been . The entire system was expected to be completed by 1975 , but it continued well into the 1980s . The new border system had an immediate effect in reducing the number of escapes . During the mid - 1960s , an average of about 1 , 000 people a year had made it across the border . Ten years later , that figure had fallen to about 120 per year . At the same time , tensions between the two German states eased with the inauguration of West German Chancellor Willy Brandt ' s " Ostpolitik " . The Brandt government sought to normalise relations between West Germany and its eastern neighbours , and produced a series of treaties and agreements . Most significantly , on 21 December 1972 the two German states signed a treaty recognising each other ' s sovereignty and supporting each other ' s applications for UN membership ( achieved in September 1973 ) . Reunification remained a theoretical objective for West Germany , but in practice the issue was put to one side by the West and was abandoned entirely by the East . The agreement had significant implications for the border . The two Germanies established a border commission ( " Grenzkommission " ) which met from 1973 to the mid - 1980s to resolve practical problems related to the border . The normalisation of relations also led to a slight relaxation in the regulations for crossing the border legally , although the border fortifications were as rigorously maintained as ever . In 1988 , the increasingly unsustainable costs of maintaining the border led the GDR leadership to propose replacing them with a high - technology system codenamed " Grenze 2000 " . Drawing on technology used by the Red Army during the Soviet - Afghan War , it would have replaced the border fences with a network of signal tripwires , seismic detectors to detect footsteps , infrared beams , microwave detectors and other electronic sensors . It was never implemented , not least because of the high costs of construction , which were estimated at 257 million East German marks .