After Independence of Bangladesh, PBSP emerged as one of the main challengers of the new Awami League-government, which it considered as Indian puppets. The first party congress was held on January 14, 1972. Sikder was elected as the Chairman of the party. In April 1973 the Purba Banglar Jatiya Mukti Front, a coalition of 11 groups, was formed. Sikder became the president of the front. After the formation of the front, the party initiated a campaign of armed struggle against the Bangladeshi state.