The number of reported victims of a recent mass rape campaign by gunmen in eastern Democratic Republic of Congo has risen to about 170, the UN says.
Aid workers had been investigating initial reports that about 60 women were raped near town of Fizi by ex-rebels who recently deserted the army
Troops from the same group were recently convicted of raping at least 50 women in Fizi on New Year's Day.
A UN envoy last year called DR Congo the "rape capital of the world".
The 16 years of unrest in eastern DR Congo have become notorious for the widespread sexual abuse of women and young girls.
More than 300 women, men and children were raped by a coalition of rebel groups in the town of Luvungi and neighbouring villages in North Kivu province within miles of a UN base in August 2010.
The latest incident occurred in villages near the South Kivu town of Fizi between 10 and 12 June but was first reported earlier this week.
A spokeswoman for the UN refugee agency, Celine Schmitt, said that organisations working near where the attacks took place estimated that some 170 women were attacked in the villages of Nakiele and Abala on the night of 11-12 June.
"During the violence armed men also looted health centres and stole livestock, which are essential for residents in this remote area," she told Reuters news agency.
Megan Hunter, from medical charity Medecins Sans Frontieres, said that a team deployed in the area's health centres had so far treated more than 100 people who said they had suffered rape or other forms of trauma.
Jean-Marie Ngoma, a member of the provincial parliament, told the UN-backed Radio Okapi that the rapes had been blamed on a group of former Pareco rebels led by Col Kifaru Niragiye, who had deserted from a military training centre near Fizi on 9 June to protest against the reorganisation of the local military command.
They then headed in the direction of the villages where the violence happened, and local administrative and civil society sources have since reported widespread looting and abuse by Col Kifaru's group, which is estimated to number between 150 and 200 men.
Margot Wallstrom, the UN's special representative on combating sexual violence in conflict, said the incident demonstrated "a continuing pattern of ill-discipline on the part of those who bear arms".
"Fuelling this pattern is the rapid integration of former rebel fighters into the national armed forces without vetting or systematic training," she said in a statement, the AFP news agency reports.
"When these forces are denied adequate pay or provisions, the risk of looting food and livestock from civilians in the vicinity is greatly heightened."
Col Kifaru was the military sector commander on New Year's Day, when his troops were accused of raping more than 50 women in Fizi town in his absence.
Nine of those men, including Col Kifaru's deputy Lt Col Kibibi Mutware, were later found guilty of crimes against humanity and jailed.