The Japanese demands were severe: a demilitarized zone extending 100 km south of the Great Wall from Beijing to Tianjin was to be created, with the Great Wall itself under Japanese control. No regular Kuomintang military units were to be allowed in the demilitarized zone, but the Japanese were allowed to use reconnaissance aircraft or ground patrols to ensure that the agreement was maintained. Public order within the zone was to be maintained by a lightly-armed Demilitarized Zone Peace Preservation Corps.