In 1965 most of the leadership of CM-LP was imprisoned. In 1968 one section, representing most of the leadership that was not jailed, started the publication O Comunista. This group later merged into the Portuguese Marxist-Leninist Communist Organization (OCMLP).
In 1969 a second conference of another tendency is held inside Portugal, through the initiative of Eduíno Vilar. They started publishing Unidade Popular in March 1969. In 1970 they formed the Communist Party of Portugal (Marxist-Leninist).