Police officials deny using any live ammunition and insist they have used "minimum force" to disperse the protests.
The death toll in Sudan from anti-coup protests since last month's military takeover has risen to at least 40.
"One martyr passed away... after he succumbed to severe wounds after being hit by live rounds to the head and the leg on November 17," the independent Central Committee of Sudanese Doctors said on Saturday.
He was aged 16, it added.
Protests on Wednesday provoked the deadliest day so far, with the toll of those killed now standing at 16, according to medics.
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.
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 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.
Human rights abuses
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.
Sudan's top general Abdel Fattah al-Burhan on October 25 declared a state of emergency, ousted the government and detained the civilian leadership.
The military takeover upended a two-year transition to civilian rule, drew wide international condemnation and punitive measures, as well as provoking people to take to the streets.
Sudan has a long history of military coups, enjoying only rare interludes of democratic rule since independence in 1956.