Sudan's ruling generals announced on Friday that nine paramilitaries had been arrested for the killing of four teenage demonstrators earlier this week after four people were killed protesting their deaths.
The move against the feared paramilitaries of the Rapid Support Forces came as talks between protest leaders and the ruling generals on a promised transition to civilian rule were due to enter a second day.
"An investigation has been launched into the incident of Al-Obaid and seven members of the RSF were immediately dismissed and handed over to civilian judges for trial," General Shamseddine Kabbashi, spokesman for the ruling military council, told reporters.
"Yesterday (Thursday), two more RSF members were arrested, so a total of nine have been detained."
The fatal shooting of the four schoolchildren and two other demonstrators during a rally against fuel and bread shortages in the city of Al-Obaid on Monday has sparked angry protests in cities across Sudan.
On Thursday, four protesters were shot dead in the capital's twin city of Omdurman, just across the Nile from Khartoum, doctors said.
The protest movement has long blamed the irregulars of the powerful RSF, whose commander General Mohamed Hamdan Daglo is deputy head of the ruling military council, for the deadly violence against demonstrators.
But after Monday's shooting, a fellow member of the military council, General Jamal Omar, too blamed the paramilitaries, who sprang out of the Janjaweed militia notorious for alleged war crimes during the conflict in Darfur.
Speaking to Egypt's Al-Ghad teleivision and other media during a tour of Al-Obaid, Omar said RSF fighters guarding a nearby bank had initially used batons to try to stop the protesters gathering.
"This action led to a reaction from some students who threw stones at the forces," Omar said.
"This made some members of the force act in their individual capacity to open fire on protesters. We have identified those who fired live ammunition that led to the killing of the six."
The RSF helped the regular army topple longtime president Omar al-Bashir in April following months of mass protests against his rule.
But its fighters, who have deployed in cities across Sudan, retain the fearsome reputation they won under the old regime.
Protesters have expressed anger at the paramilitaries' apparent impunity. "Where is the investigation committee?" demonstrators chanted in north Khartoum on Thursday.
Ongoing talks
Talks between protest leaders and the generals were suspended after the Al-Obaid killings, which drew international condemnation, including from their Ethiopian mediator.
But the negotiations eventually got under way on Thursday and were due to resume on Friday evening.
On the table are the remaining details of the political transition set out in a landmark power-sharing deal signed on July 17.
They include the powers of the proposed joint civilian-military ruling body, the deployment of security forces and immunity for the generals over protest-related violence.
"Both sides agreed to meet today at 8 pm (1800 GMT) to complete the negotiations," African Union mediator Mohamed El Hacen Lebatt told reporters.
Protest leaders were upbeat. Negotiator Ibrahim al-Amin predicted "good news" from Friday evening's second session.
The talks have repeatedly been suspended and remained deadlocked for weeks after a brutal raid on a protest camp in Khartoum on June 3 widely blamed on the RSF.
At least 127 people were killed, according to doctors linked to the protesters. Officials have given a much lower death toll.
It took intense mediation from African Union and Ethiopian diplomats to bring the two sides back to the negotiating table.