Congo and Rwanda-backed rebels on Saturday signed a declaration of principles in Qatar to end decadeslong fighting in eastern Congo that commits them to a permanent ceasefire and a comprehensive peace agreement to be signed in one month.

A final peace deal is to be signed no later than Aug. 18, and it "shall align with the Peace Agreement between Congo and Rwanda” facilitated by the U.S. in June, according to a copy of the declaration seen by The Associated Press.

The agreement of principles touches on most of the highlights of the peace deal Congo and Rwanda signed June 27. It is the first direct commitment by both side since the rebels seized two key cities in eastern Congo in a major advance.

Backed by neighboring Rwanda, the M23 is the most prominent of more than 100 armed groups fighting for control in Congo’s mineral-rich east. With 7 million people displaced in Congo, the U.N. has called the conflict in eastern Congo “one of the most protracted, complex, serious humanitarian crises on Earth.”

It was not immediately clear what the specific terms of a final peace agreement would be and what concessions would be made. M23 had been pushing for the release of its members held by Congo's army, many of them facing the death sentence. Congo had requested the withdrawal of the rebels from seized territories.

A key issue has been whether Rwanda will pull their support for the rebels, including the thousands of troops that the United Nations experts said are in eastern Congo.

When Rwanda and Congo signed the peace deal in Washington, Rwandan Foreign Minister Olivier Nduhungirehe said Rwanda agreed to lift its “defensive measures” — suggesting a reference to its troops eastern Congo — once Congo neutralizes an armed group whose members Kigali accuses of carrying out the 1994 genocide in Rwanda.

Analysts have say it is going to be difficult for the M23 rebels to withdraw from the eastern Congolese cities of Goma and Bukavu seized earlier this year and that it would depend on concessions Congolese authorities agree to make.