Witnesses say security forces were trying to prevent swelling numbers of demonstrators from marching towards the presidential palace, the military's seat of power in the heart of the capital city.
Sudanese security forces have fired tear gas at hundreds of protesters who rallied for a second day in a row in the capital against last year's military coup, witnesses said.
On Friday, demonstrators massed again near the presidential palace in Khartoum a day after at least nine people were killed during mass rallies against the military takeover led by army chief Abdel Fattah al Burhan last October.
"The people want to bring down Burhan," activists chanted while others, carrying photos of people killed in protest-related violence, yelled: "We call for retribution!"
The death toll from protest-related violence has reached 113 since the coup, with the latest fatality reported on Friday after a protester died from wounds sustained at a June 24 protest, according to anti-coup medics.
Sudan's police meanwhile accused protesters of wounding 96 police and 129 military officers, "some critically", on Thursday, as well as damaging vehicles and setting fires.
Attempts for mediation
The United Nations, African Union and regional bloc IGAD have tried to facilitate talks between the generals and civilians, but they have been boycotted by the main civilian factions.
It was the anniversary of 2019 protests demanding that the generals who had ousted Bashir in a palace coup earlier that year cede power to civilians.
Those protests led to the formation of the civilian-military transitional government that was toppled in last year's coup.