The Democratic Republic of Congo and the M23 rebel group signed a framework agreement in Doha on Saturday aimed at ending fighting in the country's east.
The deal has resulted in thousands killed and hundreds of thousands displaced this year.
Representatives from both sides participated in the ceremony in the Qatari capital.
The agreement is part of efforts supported by the United States and Qatar to address decades of conflict threatening regional stability.
U.S. and Qatari officials described it as a significant but preliminary step.
The framework includes eight protocols with details still requiring agreement on six of them.
U.S. envoy Massad Boulos noted slow progress on the initial two protocols covering prisoner exchanges and ceasefire monitoring. He told reporters:
Yes, people were expecting to see probably some immediate results on the ground, but this is a process ... This is not a light switch that you just switch on and off.
The agreement builds on a July declaration of principles and an October deal on ceasefire monitoring.
Qatar has hosted direct talks since April focused on preconditions and confidence-building.
Qatar's Minister of State for Foreign Affairs Mohammed bin Abdulaziz Al-Khulaifi stated the deal advances peace through confidence and commitment.
M23 seized Goma in January and expanded control in North Kivu and South Kivu provinces.
Rwanda denies supporting M23 despite allegations.
Fighting continues with both sides accusing each other of violations.
Other armed groups remain active as 28 people were killed by Islamic State-allied militants in North Kivu on Friday.
The framework addresses humanitarian access return of displaced people and judicial protection but root causes including mistrust persist.
Former U.S. envoy Tibor Nagy emphasized the need for extensive follow-up rather than superficial processes.