The agreement, ratified on Saturday in Juba, the capital of South Sudan, was aimed at dispute settlement in the western region of Darfur and in the southern states of Blue Nile and South Kordofan.
Groups from other areas have also signed, but those in the east argue that the two sides participating in the "eastern track" of the peace process are not political forces on the ground.
The agreement aims to end decades of violence in Sudan and unite the nation behind a democratic transition following the ouster in April 2019 of former leader Omar al-Bashir.
The two most involved parties in the West and South, however, did not sign, and analysts claim that during talks, the military and civilian authorities now sharing power were not widely consulted by local communities.
Eastern Sudan's politics are volatile due to the violent tribal conflicts that have recently affected Port Sudan and Kassala, the positioning of regional forces, like wealthy Gulf states, and frustration at a long-running economic crisis and the lack of public services.
Staff at the southern port, Sudan's largest container terminal, and at the southern port of Suakin were on strike over the peace agreement, stated Aboud el-Sherbiny, President of the Union of Port Sudan Workers.
Maritime Business World