About 200 unemployed graduates held a rare protest to demand jobs in a key oil-producing region of Sudan on Monday, a witness said, the second such demonstration in a month in the politically sensitive area.

Anti-government protests in Sudan have failed to attract mass support but Monday's protest in the South Kordofan state could raise pressure on the government since the area is dominated by the Arab Misseriya nomads, a well-armed group that has supported Khartoum in the past.

Police, who have used tear gas on, beaten or arrested dozens in short-lived protests elsewhere, surrounded the two-hour demonstration in the town of Al-Fula but did not intervene, the witness said.

The Misseriya tribe was mobilised by Khartoum during the country's north-south civil war as proxy militia. South Kordofan borders both Darfur and south Sudan, which earlier this year voted to secede from the north.

The town of Al-Fula also lies in Sudan's oil Block 6, controlled by a consortium led by CNPC of China.

Security forces later on Monday used batons to break up an protest by about 100 students outside a university in Khartoum demanding a change in government, witnesses said. At least one demonstrator was detained, a youth activist said.

Two people, one with blood on his head and shirt, could be seen being taken away in a police vehicle, though it was unclear if they were protesters or security force members, a Reuters witness said.

Soaring prices and a lack of jobs have fuelled anger among Sudanese, but attempts by youth groups to emulate uprisings in Tunisia and neighbouring Egypt have so far failed to gather momentum and have been swiftly quashed by security forces.