The United States voiced gratitude to Qatar, which mediated the agreement between Sudan`s President Omar al-Bashir and the Liberation and Justice Movement signed in the presence of another four African leaders.
"This agreement is a positive step forward on the road toward a lasting solution to the crisis in Darfur," State Department spokesman Mark Toner said in a statement.
"We will continue to press those armed movements which refuse to participate in the peace negotiations -- particularly the Sudan Liberation Army factions of Abdelwahid Nur and Minni Minnawi -- to engage fully in the peace process," he said.
Another main armed group, the Justice and Equality Movement, criticized the accord as failing to solve Darfur`s problems and said it merely offered jobs to those who signed it.
Toner also urged Sudan to "affirm its openness" to further negotiations on a comprehensive peace in Darfur.
At least 300,000 people have been killed in Darfur and 1.8 million people fled their homes since the conflict broke out in 2003 between non-Arab rebels and the Arab-dominated Khartoum regime, according to the United Nations.
The government puts the death toll at 10,000. (*)