"Eyewitnesses in Kiwanja [near Rutshuru, 70km north of Goma in North Kivu] told Human Rights Watch [HRW] that at least 20 persons were killed and another 33 wounded during a battle for the town and in the clean-up operations by Nkunda's forces that followed," said Anneke van Woudenberg, senior Africa researcher at HRW.
On 6 November, CNDP rebels re-seized Nyanzale, Kikuku and Kiwanja villages before leaving, said Jean-Paul Dietrich, the MONUC (UN Mission in Congo) military spokesman.
"The army abandoned its positions with the advance of the rebels, who withdrew to the surrounding hills shortly after their attack on these villages," said Dietrich.
MONUC has opened an investigation into the killings.
"Armoured cars came down yesterday [6 November] to prevent attacks continuing this morning and a team went to the site to verify the allegations," said Dietrich.
MONUC's spokeswoman in Goma, Sylvie van den Wildenberg, said the force was very worried about possible atrocities in Kiwanja.
According to HRW, UN peacekeepers based in the area were apparently unable to protect civilians from attack.
"Rebel leader Laurent Nkunda's forces and government-backed Mai Mai militias deliberately killed civilians in Kiwanja ... on November 4-5, 2008. UN peacekeepers based in the area were apparently unable to protect civilians from attack," Van Woudenberg explained.
However, MONUC spokesman Madnodje Mounoubai countered that when fighting began, civilians headed to the MONUC camp in large numbers. "So the first thing MONUC did was to make sure those who came to the camp received protection and security."
Government spokesman Lambert Mende said that "such crimes should not go unpunished" and condemned "in the strongest terms the criminal behaviour of this armed group, Laurent Nkunda's CNDP".
For its part, the CNDP said those who died were not civilians. "We took the precaution of gathering the population in a stadium and those who remained were soldiers or fighters in civlian clothes who fought with our men," said the CNDP spokesman, Bertrand Bismwa.
According to HRW, after re-establishing control of Kiwanja on 5 November, Nkunda's rebels ordered the population of some 30,000 inhabitants to leave the town and then systematically sought out and killed civilians, particularly men, whom they accused of supporting their enemies.
People in Kiwanja told HRW they heard screams into the night and saw bodies on the streets the following morning.
One of those killed in Kiwanja was Alfred Nzonzo Bitwahiki, a journalist working for a local radio station, Radio RACOU.
Witnesses also reported that pro-government Mai Mai militias targeted civilians in Kiwanja, including those they accused of supporting Nkunda's forces.
On 4 November, at least six people, including a foreign journalist, Thomas Scheen, of the German newspaper Frankfurter Allgemeine Zeitung, were abducted by Mai Mai militias in Kiwanja. To date, their whereabouts are unknown.