Goma, Congo - The Congolese army has freed about 100 children who had been kept as prisoners by a militia operating in the centre of the country, the UN mission to Congo (MONUSCO) said Wednesday.

The children, aged between 4 and 16, were freed by the army as it clashed with the Kamwena Nsapu militia between December 2016 and February 2017.

The latest group of 20 children, who included a girl, was released on February 23, MONUSCO representative Charles Antoine Bambara said at a press conference in the capital Kinshasa.

The Kamwena Nsapu was believed to have forced or pressured families to hand over their children, who were used as military scouts or guardians of objects believed to have magical powers. Some of them had been with the militia since August 2016.

The children were armed with knives and sticks, and underwent rituals to make them believe that they were invulnerable to bullets, MONUSCO said in a statement.