Huge crowds protested against possible foreign intervention in the war-torn western province on Wednesday shortly after gathering at the presidential palace.
The marchers carried banners in English and Arabic bearing slogans such as "Darfur is the Graveyard of the US" and "No to Foreign Intervention".
Many of the marchers were wearing students' uniforms, though one contingent was conspicuous by black shirts and red headbands identifying them as "Martyrs Brigades".
The protest was organised by an umbrella group of political parties called the Association of Faith and the Motherland.
The UN Security Council passed a resolution last Friday giving Khartoum 30 days to disarm the so-called Janjawid nomadic militias accused of committing atrocities against Darfur's non-Arab population.
The resolution also requires Khartoum to allow free access for humanitarian groups and to secure the province to allow about 1.2 million displaced people and 150,000 refugees in neighbouring Chad to return home or face international action.
The UN estimates that up to 50,000 people have been killed in Darfur and more than a million have fled their homes.