The talks are part of efforts to resolve a civil war that has claimed about 10,000 lives since it erupted in western Sudan in February 2003.
Having initially started as a rebellion, prompted by the region's dire poverty, the conflict has displaced about one million people inside Sudan and forced more than 100,000 others to flee to neighbouring Chad.
The conflict is described by the United Nations as the world's worst ongoing humanitarian disaster.
A Sudanese government delegation and representatives of the rebel Sudan Liberation Movement (SLM) and the Justice and Equality Movement (JEM), who agreed on a truce on 8 April, held two hours of talks on Friday in the presence of Chadian negotiators.
Meanwhile in Geneva, the top UN human-rights forum adopted a relatively soft text on the alleged government-backed atrocities in Darfur - prompting the US to demand a second vote for stronger action.
"The horrific events in Darfur demand strong action," said US delegation chief, Richard Williamson.
Arab militias, blamed for the atrocities in Darfur, are allegedly patronised by the government in Khartoum.
The rebels of Darfur, inhabited mainly by non-Arab Muslims, are pushing for economic development and more equitable sharing of meagre national resources.
Sudan denies arming the militias, who have looted and burned African villages.