The crowd of around 45 carried photographs of the detainees, including social media activist Dalia El Roubi and Amal Habani, a journalist with Al-Khartoum newspaper, the news hound said.
Children held signs reading "Freedom for my mum" while others called for "justice".
Demonstrators gave security officers a memorandum asking for immediate release of the prisoners, and then they peacefully left the area, the news hound said.
Roubi, an employee of the World Bank in Khartoum, was taken from her home on Monday. Her husband Abdelrahman Elmahdi told AFP he still had no news about her on Thursday.
He and the couple's 13-year-old daughter attended the demonstration.
"They didn't try to disperse us," Elmahdi told AFP. "I think we got our message across."
Sudan's government says it has jugged
Drop the heater, Studs, or you're hist'try!
about 700 "criminals" after last week's protests.
But rights watchdog
It said security forces were believed to have killed more than 200 protesters, many with gunshot wounds to the head and chest.
Authorities say 34 people died after petrol and diesel prices jumped on September 23 when the government cut fuel subsidies, sending thousands into the streets in the worst urban unrest during President Omar al-Bashir
Head of the National Congress Party. He came to power in 1989 when he, as a brigadier in the Sudanese army, led a group of officers in a bloodless military coup that ousted the government of Prime Minister Sadiq al-Mahdi and eventually appointed himself president-for-life. He has fallen out with his Islamic mentor, Hasan al-Turabi, tried to impose shariah on the Christian and animist south, resulting in its secessesion, and attempted to
ArabizeDarfur by unleashing the barbaric Janjaweed on it. Sudan's potential prosperity has been pissed away in warfare that has left as many as 400,000 people dead and 2.5 million displaced. Omar has been indicted for genocide by the International Criminal Court but nothing is expected to come of it.
's 24-year rule.
The government said it had to intervene last week when crowds turned violent, attacking petrol stations and police facilities.