0806 GMT August 18, 2019
The planned "million-man" march is being seen as a test for protest organizers whose movement has been hit by a June 3 raid on a Khartoum sit-in and a subsequent internet blackout that has curbed their ability to mobilize support, AFP reported.
Dozens of demonstrators were killed and hundreds wounded when armed men in military fatigues stormed the sit-in outside army headquarters, shooting and beating protesters who had camped there since April 6.
On Sunday, police fired tear gas in a northern Khartoum district as thousands of protesters chanted "civilian rule, civilian rule," witnesses said.
Security forces also fired tear gas at demonstrators in the eastern town of Gadaref, a witness said.
The latest demonstrations come at a time when Ethiopia and the African Union (AU) are jointly mediating between the protesters and generals.
Thousands also launched protests in the cities of Port Sudan, Al-Obied, Madani and Khasma el-Girba, witnesses said.
The umbrella protest movement, the Alliance for Freedom and Change, said demonstrators in Khartoum and its twin city of Omdurman would march to the homes of some of the protesters killed on June 3.
About 130 people have been killed since the crackdown, the majority of them on that day, according to doctors close to the alliance.
The Health Ministry says 61 people died nationwide on June 3.
The ruling military council insists it did not order the dispersal, but acknowledged "excesses" after orders were given to purge a nearby area allegedly notorious for drug peddling.
Tensions remain high since the June 3 raid, which followed the collapse of talks over who should lead a new governing body – a civilian or soldier.
Ethiopia and the AU have proposed a blueprint for a civilian-majority body, which the generals say could be a basis for resuming talks.
Protesters had initially gathered at the military headquarters to seek the army's support in ousting longtime ruler Omar al-Bashir.
They kept up their sit-in to demand civilian rule after the generals deposed the president on April 11.