Sudanese protesters blocked roads in several parts of the capital Khartoum with stones and burning tyres, Reuters reported a witness saying, after troops tried to disperse a sit-in by force.
The witness said protesters were demanding that the country's Transitional Military Council (TMC) hand over power to civilians.
A leader of Sudan's protest movement called the storming by security forces of the protest camp a "coup" against the uprising that led to the ouster of President Omar Al-Bashir.
"We will confront it by escalating protests, marches and full civil disobedience," said Khalid Omar Yousef, a leader of the Declaration of Freedom and Change Forces.
Sudanese Transitional Military Council said that criminal elements near a Khartoum protest site were being targeted in the raid by security forces, denying that authorities were trying to clear the camp.
Lieutenant General Shams El Din Kabbashi also told Reuters that the TMC remained committed to talks with the protesters and was ready to hold a meeting soon.
Kabbashi earlier told Abu-Dhabi-based Sky News Arabia talks on a civilian transition were expected to resume "today or tomorrow".