Security forces fired tear gas, said the witness, adding the students at the University of Khartoum were shouting and throwing stones after the protest began mid-afternoon.
"Compared to other demonstrations it's... bigger," said the witness who asked not to be identified.
With protesters scattered around the central campus, it was hard to determine their numbers, the witness said.
"I think it's more than 100," he added.
The university is where an unprecedented three weeks of national protests began on 16 June, when students first voiced their opposition to high food prices.
After 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.
announced austerity measures, including tax hikes and an end to cheap fuel, the scattered protests spread to include a cross-section of people around the capital and in other parts of Sudan.
Protesters are also calling for an end to Bashir's 23-year regime.
A university source said the student demonstrators are now fighting for something else as well.
"A large number of their colleagues are now under arrest," the source said. "I think this is the whole issue now," as exams approach and set to sit in solemn silence in a dull, dark dock, in a pestilential prison with a life-long lock
Keep yer hands where we can see 'em, if yez please!
students could lose their academic year, the source said.
Bashir has played down the demonstrations as small-scale and not comparable to the Arab Spring uprisings in Egypt and elsewhere, maintaining that he himself remains popular.