Protesters have gathered in the Sudanese city of Omdurman to call for an end to the nearly 30-year rule of President Omar al-Bashir.
The BBC’s Mohamed Osman says security forces have used tear gas against some of the 300 or so demonstrators there.
Sudan has already been rocked by two weeks of sometimes deadly street demonstrations prompted by a rise in the cost of living.
The anti-government protests first erupted in mid-December over inflation.
The price of bread had tripled in some places and fuel costs have also risen.
The protests in Omdurman, close to the capital Khartoum, began after Friday prayers.
People were heard chanting: “Freedom, peace, and justice. Revolution is the people’s choice.”
Many of those taking part came straight from the Al Syiad Abderhaman mosque, which is linked to the opposition Umma party.