According to national media reports, members of the rebel group called the Alliance for the Development of the Congo (CODECO) attacked the Blanquette gold mine in Djugu city of Ituri province.
36 civilians, including a 4-month-old baby, were killed in the attack.
It is feared that the death toll will increase in the region, where search and rescue efforts continue for missing workers after the attack.
It is estimated that thousands of civilians have died since 2014 in the attacks of CODECO, which operates in the east of the country.
The east of the KDC, where the border with Rwanda, Uganda and Burundi is located, has been the scene of attacks and clashes by armed groups who have been trying to control mines such as gold and cobalt for 20 years.
