"One martyr passed away... after he succumbed to severe wounds after being hit by live rounds to the head and the leg on 17 November," the independent Central Committee of Sudanese Doctors said. He was aged 16, it added.
Most of those killed on Wednesday were in North Khartoum, which lies across the Nile river from the capital, medics said.
Police officials deny using any live ammunition and insist they have used "minimum force" to disperse the protests. They have recorded only one death, among demonstrators in North Khartoum.
'Abuses and violations'
On Friday, small groups of protesters rallied in several neighbourhoods after prayers against the military coup, especially in North Khartoum, where people were seen building barricades across the roads. Security forces sporadically fired teargas to disperse them.
The United States on Friday condemned the deadly crackdown.
"We call for those responsible for human rights abuses and violations, including the excessive use of force against peaceful protesters, to be held accountable," State Department spokesman Ned Price said in a statement.
Washington said Sudanese should "be free to voice their opinions without fear of violence", and called for those arrested since the takeover to be freed.
"In advance of upcoming protests, we call on Sudanese authorities to use restraint and allow peaceful demonstrations," the US added.
The Sudanese Professionals Association (SPA) have urged protesters to keep up their campaign, reporting Friday that security forces had "stormed homes and mosques" in North Khartoum.
The SPA is an umbrella of unions which were instrumental in the months-long demonstrations that ousted president Omar al-Bashir in April 2019.
Sudan has a long history of military coups, enjoying only rare interludes of democratic rule since independence in 1956.
Burhan, the top general, insists the military's move "was not a coup" but a step "to rectify the transition" as factional infighting and splits deepened between civilians and the military under the now-deposed government.
He has since announced a new civilian-military ruling council in which he kept his position as head, along with a powerful paramilitary commander, three senior military figures, three ex-rebel leaders and one civilian.
But the other four civilian members were replaced with lesser known figures.