At least 21 people, including women and a baby, were killed over the weekend in eastern Democratic Republic of Congo, the UN peacekeeping mission there has said.

Most of those killed appeared to have been hacked to death on Friday and Saturday in villages not far from Beni in Congo's North Kivu province, according to a statement on Monday by Martin Kobler, head of the peacekeeping mission, known as MONUSCO.

It was not clear who was responsible for the killings, but they highlighted the challenge facing Congo's army and UN forces pacifying Congo's east despite the defeat of M23 rebels, the most serious uprising in years.

"These atrocities will not go unpunished," Kobler said in a statement. Three girls appear to have been raped and then beheaded while one of the victims was just months old, the statement added.

The statement did not say who was believed to be responsible.

Congo-based Ugandan ADF-NALU rebels operate in the region alongside a plethora of other groups still plaguing civilians.

Source: Agencies