The PKI re-emerged on the political scene after the 1945 surrender of Japan and actively participated in the Indonesian National Awakening; many armed units were under PKI control or influence. Although PKI militias played an important role in fighting the Dutch, President Sukarno was concerned that the party's growing influence would eventually threaten his position. Because the PKI's growth troubled the right-wing sectors of Indonesian society and some foreign powers (especially the vigorously anti-communist United States), its relationship with the other forces also fighting for independence was generally difficult.