Six soldiers have gone on trial in the Democratic Republic of Congo in connection with the killing of more than 40 anti-UN protesters last week.
Amongst them are two senior officers alleged to have instructed soldiers to open fire on the banned demonstration.
The protest took place in the eastern city of Goma to demand the withdrawal of UN and regional peacekeepers.
Protesters accuse them of failing to protect civilians against decades of attacks by rebels in the east.
The case is being held at a military tribunal in Goma, the capital of mineral-rich North Kivu province where many rebel groups operate and where M23 fighters captured large swathes of territory last year.
The soldiers were charged with crimes against humanity and of violating orders.
One of the six defendants, Col Mike Mikombe, heads the elite Republican Guard in Goma. He was the only one of the accused who spoke to deny the charges at the start of proceedings on Tuesday.
It is unclear whether the defendants themselves fired any shots during last Wednesday's protest.
A religious sect had organised the demonstration, which the authorities had banned. The UN peacekeeping mission in eastern DR Congo (Monusco) has faced several protests since last year.
Monusco currently has almost 18,000 personnel in the country, including more than 12,000 soldiers. It has been agreed that the force will withdraw after the elections in December are held.
The government's most recent update on the anti-UN protest in Goma put the death toll at 43, which includes a police officer who was allegedly killed by the protesters. Fifty-three people were reported to have been injured.
However, the UN Human Rights Office said that the death toll could be higher and military prosecutor Colonel Michel Kachil told the tribunal that 56 people had been killed.
More than 150 people were also arrested during the crackdown by the security forces.
The incident has sparked outrage across DR Congo and Human Rights Watch has called the soldiers' response "callous" and "unlawful".
The military tribunal comes after the country's interior and defence ministers travelled to Goma over the weekend to investigate the incident.
The government subsequently announced it was recalling military governor of North Kivu General Constant Ndima to the capital, Kinshasa, for "consultations", the AFP news agency reports.
On Wednesday it emerged that Jacques Ndulu Ichaligonza had replaced Gen Ndima as acting military governor.
North Kivu and another eastern province - Ituri - were put under martial law in May 2021 in an attempt to combat the rebels and militias.
Eighteen months later, a regional force was deployed to eastern DR Congo to aid the military's response.
Despite the anti-peacekeeping protests, East African heads of state unanimously agreed to extend the deployment of their force on Tuesday.