The pro-democracy Central Committee of Sudan Doctors says a male protester was shot in the stomach by security forces, while police say protesters fatally stabbed a police brigadier general.
A Sudanese protester has been killed during demonstrations against the military that staged a coup in October derailing a transition to civilian rule, medics say.
The demonstrator's death on Thursday came after police claimed anti-coup protesters had stabbed to death a police brigadier general in the capital Khartoum.
The latest fatality was identified as Al Reeh Mohammad, and his death brings to 64 the number of protesters killed since the October 25 military coup led by General Abdel Fattah al Burhan.
Hundreds have been wounded in a security crackdown, according to the medics.
Thursday's rallies converged from several parts of Khartoum, and came after a United Nations bid to facilitate talks between rival Sudanese factions received tepid support.
During a rally in Khartoum, Brigadier General Ali Bareema Hamad, "fell martyr while doing his duties and securing protests", a police statement said.
Hamad "received deadly stabs by groups of protesters...in different parts of his body," police spokesperson Idris Abdalla Idris told Sudan TV.
Hamad's was the first fatality announced among security forces since protests calling for a return to civilian rule began more than two months ago.