was brief. The party now worked on a variety of fronts, such as Gerindo and trade unions. It began working amongst Indonesian students in the Netherlands within the nationalist organization Perhimpunan Indonesia, which the party would soon control. Resurgence National revolution 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. The PKI and the Socialist Party (Partai Sosialis) formed a joint front, the People's Democratic Front, in February 1948. Although the front did not last, the Socialist Party later merged with the PKI; by this time, the Pesindo militias were under PKI control. Madiun affair On 11 August 1948, Musso returned to Jakarta after twelve years in the Soviet Union. The PKI politburo was reconstructed, and included D. N. Aidit, M. H. Lukman and Njoto. After signing the Renville Agreement in 1948, many of the republican armed units returned from zones of conflict; this gave the Indonesian republicans some confidence that they would be able to counter the PKI militarily. Guerrilla units and militias under PKI influence were ordered to disband. In Madiun, a group of PKI military which refused to disarm were countered in September of that year; the confrontations sparked a violent uprising, which provided a pretext to clamp down on the PKI. It was claimed by army sources that the PKI had announced the proclamation of a Soviet Republic of Indonesia on 18 September, with Musso as president and Amir Sjarifuddin as prime minister. At the same time, however, the PKI had denounced the uprising and appealed for calm. The uprising was suppressed by republican troops, and the party experienced another period of repression. On 30 September, Madiun was taken over by republican troops of the Siliwangi Division. Thousands of party members were killed, and 36,000 were imprisoned. Amongst the executed were several leaders, including Musso (who was killed on 31 October, allegedly while trying to escape from prison). Although Aidit and Lukman went into exile in