The pro-democracy Central Committee of Sudan Doctors said the protester was killed in Omdurman, across the Nile river from the capital Khartoum.

The latest in near-weekly protests against the power-grab comes as Sudan reels from the impact of deadly ethnic clashes in a land dispute that broke out on July 11 in southern Blue Nile state, in which 105 people were killed and 291 were wounded.

The clashes in Blue Nile between members of the Berti and Hausa ethnic groups then triggered furious protests in several cities elsewhere in Sudan this week, with Hausa members taking to the streets including in Khartoum demanding justice for their comrades.

Sudan, one of the world's poorest countries, is also mired in an economic crisis that has deepened since last year's power-grab led by army chief Abdel Fattah al-Burhan.

Earlier this month, Burhan vowed in a surprise move to make way for a civilian government.

But the country's main civilian umbrella group rejected his move as a "ruse" and protesters have continued to press the army chief to resign.

Activists say they want to resume large rallies on Sunday, calling for a demonstration to encourage "peaceful coexistence" between the country's multiple ethnic groups after the bloodshed in Blue Nile.