MONUSCO said the vehicle in which they were travelling came off the road and overturned after sliding into a ravine about 13 kilometres (eight miles) south of Kitchanga in North Kivu province.

"A blue helmet from the Moroccan rapid deployment battalion and a Congolese language assistant lost their lives in the accident," a statement said.

Four other Moroccan soldiers were injured and taken to the UN hospital in the provincial capital Goma, which is held by the M23 armed group.

With nearly 13,800 personnel, as of February, according to UN figures, MONUSCO is one of the biggest UN peacekeeping forces.

More than 400 members -- civilians and military -- have been killed since its operation started in 1999.