Six people, at least four of whom were children, were shot dead when security forces broke up a student protest in El-Obeid, about 400km southwest of the capital, Khartoum, opposition-linked doctors said.
The teenagers were rallying against fuel and bread shortages, residents said.
Hundreds took to the streets of El-Obeid on Wednesday to denounce the killings. Many carried Sudanese flags and photos of those killed as they gathered in the city centre.
“It is unacceptable that young people are being killed,” protester Fatima Mohamed told AFP news agency. “These schoolchildren were only chanting slogan. Why were they shot with bullets?”
“Those who committed these crimes must be brought to justice.”
Al Jazeera’s Hiba Morgan, reporting from neighbouring Ethiopia, said the only body that could currently set up an investigation into the children’s killings is the ruling Transitional Military Council (TMC).
“Protesters are saying that they do not believe the TMC can set up an independent, free and fair investigation committee so they’re demanding that there should be an investigation committee that is formed by the opposition coalition and with the help of international mediators,” she said.
She added that the Sudanese Professionals Association (SPA) – that has been leading the protests in the country since December – held a press conference on Wednesday and said it knows who is responsible for killing the protesters and blaming the TMC and the governor of North Kordofan state, where El-Obeid is located, for inaction.
The TMC said in a statement distributed by state-owned news agency SUNA that kindergartens, primary and high schools would be closed “until further notice”.
The children’s deaths came at a time of heightened tension between the TMC and the main opposition coalition – the Freedom and Change alliance (FFC) – and delayed already stalled talks over a transition deal following the overthrow of long-time ruler Omar al-Bashir in April.
On Wednesday, AU’s Mohamed Hassan Lebatt also called upon the TMC and the opposition coalition to sign a constitutional declaration that they have been wrangling over for weeks.
Thousands of protesters took to the streets in Sudan, furious over the killing of school children in El-Obeid by security forces.
Security forces responded with tear gas and ammunition. A curfew has been imposed & schools suspended. pic.twitter.com/ox4qbUKjBH
— Al Jazeera English (@AJEnglish) July 31, 2019
A joint legal committee from both sides is due to meet later on Wednesday, when it is expected to complete its work on the document, he told a news conference.
A date will be set for signing the constitutional declaration after the meeting, Lebatt said, adding he hoped that would happen quickly.
“Any delay in signing an agreement will not reflect only on Sudan but also on the region and the entire African continent,” he warned.
Al Jazeera and news agencies