The defendants' lawyers have said they will appeal the decision, while two others standing trial were acquitted.

The death penalty is often handed down in the Democratic Republic of Congo, but it has not been applied for 20 years and is systematically commuted to life imprisonment.

During closing arguments on Friday, a senior public prosecutor had not requested the death penalty but life imprisonment for the main defendant, Colonel Mike Mikombe.

But the court handed Mikombe the death sentence with a charge of "murders", although charges of crimes against humanity were dropped.

The prosecutor also asked for sentences ranging between 10 and 20 years for the five other defendants.

The six soldiers had been on trial since September 5 over the deadly crackdown against a religious sect that called for demonstrations against the United Nations' presence in the region.

The crackdown saw 57 people killed, according to the latest official toll, and has led to renewed tensions in the North Kivu capital of Goma, an area plagued by violence by armed groups.