The U.S. State Department is calling for the resumption of peace talks between the Sudanese government and armed rebel movements in Darfur.
The State Department made the comments on Wednesday at the end of a two-day workshop with Darfuri rebel groups and civil society leaders at the U.S. Institute of Peace in Washington.
The workshop included members of the Justice and Equality Movement (JEM), as well as the Justice and Liberation Movement (JLM) and the Sudan Liberation Army-Minni Minnawi (SLA-MM).
The Sudanese government did not participate in the meeting, which the U.S. described as "frank and productive."
In July, the JLM signed a pact with the Sudanese government at a peace conference in Doha, Qatar, but the accord was rejected by the region's main rebel groups.
The State Department said the Doha agreement is a "step forward in the peace process" and urged both sides to implement it "fully and transparently."
It also called on Khartoum to "remain open and flexible" to negotiating a comprehensive peace deal with non-signatory rebel groups.
The Justice and Equality Movement, Darfur's most powerful rebel group, refused to sign the Doha pact, saying it did not resolve human rights violations, the distribution of power and wealth or the compensation and return of displaced persons.
A JEM spokesperson said Wednesday the workshop served as an opportunity to advocate a controversial new rebel alliance.
Last week, the JEM and two branches of the Sudan Liberation Army announced the formation of the Sudan Revolutionary Front, which aims to topple the government of Sudanese President Omar al-Bashir.
The U.N. has condemned the alliance, saying it is "counterproductive" and could spark further violence.
The United Nations says more than 300,000 people have been killed in the Darfur conflict, and 2.7 million others have been displaced. Sudan's government puts the death toll at 10,000.
The ICC has indicted Sudanese President Bashir on charges of genocide and war crimes in Darfur. The Sudanese leader has denied the charges and rejected the court's authority.
Rebels in Darfur took up arms against the government in 2003, accusing Khartoum of neglecting their region.