Hundreds of Sudanese joined anti-government demonstrations in Khartoum, as protests against spending cuts flared for a second week despite a security crackdown.
Sudan's police force ordered its officers to put an end to the demonstrations "immediately".
Protests spread throughout the capital a day earlier expanding beyond the core of student activists initially involved.
Anger has arisen due to a raft of austerity measures meant to tackle a €1.9bn budget deficit.
Activists have tried to use discontent to trigger an Arab Spring-style uprising against the government of President Omar Hassan al-Bashir.
Security forces used teargas and batons to break up the demonstrations in several neighbourhoods.
Tear gas hung in the air, broken rocks were strewn across the street and smoke rose from burning tyres amid a heavy security presence in the Al-Daim neighbourhood.
It is estimated that 300 to 400 demonstrators were scattered in small groups on different streets.
Clusters of demonstrators moved through side streets, blocked roads, burned tyres and chanted "freedom, freedom", and "the people want to overthrow the regime".
In the central Khartoum Three area, around 200 demonstrators threw rocks at police, who fired tear gas to break them up.
Opposition leaders and youth activists say they share complaints with Arab Spring protesters such as unemployment and corruption.
The opposition chiefs have called for more demonstrations to press for greater democracy and measures to control price rises.
Government officials have played down the protests, and have so far said they will press forward with spending cuts which they say are needed to heal the ailing economy.