People attend a rally calling for an end to ethnic tensions and civil conflict following an escalation of violence in Blue Nile state and Darfur, in Khartoum, Sudan July 26, 2022. AFP
The unidentified protester was hit "by live bullets to the face by military forces" during protests in Omdurman, the capital's twin city, the Central Committee of Sudan Doctors said.
Tuesday's death brings to 116 the number of protesters killed in the crackdown since last October's take over led by army chief Abdel Fattah al-Burhan, the committee said in a statement.
Sudan's main civilian group, the Forces for Freedom and Change (FFC), had called for mass demonstrations with hashtags urging co-existence and a "unified nation".
In the capital Khartoum, demonstrators marched with the national flag and chanted "Sudan is a nation for all people!"
Protesters also chanted "No to tribalism and no regionalism!" while others called on the military "to go back to barracks", according to an AFP correspondent.
Senior civilian politicians including Mohamed al-Fekki and ex-minister Khaled Omar Youssef were seen at the demonstrations.
The two men, key leaders of the FFC, were among civilian officials who have been removed from power since the military take over in last October.
Some pro-democracy activists and protesters opposed the FFC's participation, saying the rallies should not be overshadowed by partisan motives, AFP correspondents said.
Near-weekly protests and deepening turmoil have rocked Sudan since last year's military take over which upended a transition to civilian rule following the 2019 ouster of president Omar al-Bashir.
Sudan has since reeled from a spiralling economic crisis and a broad security breakdown which has seen a spike in ethnic clashes in its far-flung regions.
On July 11, tribal clashes over a land dispute erupted in southern Blue Nile state, leaving at least 105 people dead and 291 wounded.
The clashes between members of the Berti and Hausa ethnic groups have since triggered furious protests in several cities, with Hausa members taking to the streets including in Khartoum to demand justice for comrades who were killed.
On July 4, Burhan pledged to step aside to make way for Sudanese factions to agree on a civilian government, but the FFC dismissed his move as a "ruse".