GOMA, Democratic Republic of Congo (Reuters) - Eleven Congolese militia fighters were jailed for life on Wednesday for raping dozens of girls as young as 18 months during ceremonies meant to give the men supernatural powers, rights groups observing the trial said.

Human rights campaigners hailed the court’s verdict as a landmark decision in a country where they say rape by armed groups is commonplace and often unpunished.

The fighters from Djeshi ya Yesu - the Army of Jesus - militia were accused of raping at least 37 girls near the village of Kavumu in Democratic Republic of Congo’s South Kivu province between 2013 and 2016, the rights groups said.

According to the prosecution, the group’s leader, provincial lawmaker Frederic Batumike, employed a spiritual adviser who told the fighters that raping very young children would give them mystical protection against their enemies.

Militia members, including Batumike, were also convicted of murder, membership in a rebel movement and illegal weapons possession. The court ruled that the rapes and murders amounted to crimes against humanity, the rights groups said.

The crimes triggered an international outcry. Rights groups accused the government of a slow response.

“This was necessary. The victims have been waiting. It’s a strong signal to anyone who would contemplate this kind of offense,” Charles Cubaka Cicura, a lawyer for the victims, told Reuters after the verdict was announced.

Millions died in eastern Congo in regional wars between 1996 and 2003, most from hunger and disease. Dozens of armed groups continue to prey on local population and fight for control of the area’s rich natural resources.

Experts say Congo has made some progress in combating sexual violence and several high-level militia and army commanders have been prosecuted in recent years, but the problem remains pervasive.

“This trial demonstrated that justice can be served in the Congo ... even when the accused wield significant power and are highly organised,” said Karen Naimer of Physicians for Human Rights, one of the groups supporting the victims.

The mobile court which set up in Kavumu village allocated $5,000 in compensation to each rape victim and $15,000 to the families of men murdered by the militia, the groups said.