Sudanese police have clashed with scores of protesters in the capital Khartoum for a third day, a witnesses said, extending demonstrations against government austerity plans to cope with an economic crisis.
Sudan has faced a widening budget gap, a depreciating currency and high inflation since South Sudan split away a year ago, taking with it three quarters of the country's oil production - previously the main source of exports and state revenues.
On Tuesday, more than 100 demonstrators blocked a street in Khartoum and scuffled with police while chanting "no, no to inflation" and "the people want to overthrow the regime," the witness said.
As on the previous two days of demonstrations, police used batons and tear gas to disperse the crowd, a witness added, requesting anonymity because of the sensitivity of the issue.
The police were not immediately available to comment.
On Monday, the police said in a statement there had been "limited" clashes with students during which several people were detained, and accused the demonstrators of trying to spark riots.
Activists said small protests had also broken out at two university campuses on Tuesday, but the claim was not immediately possible to verify independently.
Social media users posted online photos and footage that purport to show the protests and the ensuing crackdown.
While the Arab-African country has avoided the sort of "Arab Spring" unrest that toppled leaders in neighbouring Egypt and Libya, small demonstrations have broken out over food prices and other issues in recent months.
The most recent protests have come partly in response to President Omar Hassan al-Bashir's unveiling of tough austerity measures on Monday, to plug a budget deficit which the finance minister put at $2.4bn.
One of the most contentious issues is a plan to gradually end fuel subsidies, a move many Sudanese fear will stoke even higher inflation. It hit 30 per cent in May.
Previous student protests in Khartoum and other university cities have failed to gain broader momentum. Opposition politicians said last week they planned to stage protests against the removal of fuel subsidies.
Sudan had been supposed to keep collecting some revenues from the roughly 350,000 barrels of oil per day of output Juba inherited on secession, under an agreement whereby the landlocked South would pay to use pipelines and other facilities in the north.
But the two have failed to agree on fees, and the dispute climaxed when the South shut down its entire output in January to stop Khartoum from confiscating some oil.
The economic fallout has piled hardships on people already exhausted by years of conflict, US trade sanctions and economic mismanagement.