(CNN) -- At least 33 women were raped on New Year's Day in a region in the Democratic Republic of Congo, said the medical group Doctors Without Borders Thursday.
"Women had been restrained with ropes or beaten unconscious with the butt of a gun before being attacked, some in front of their children." said Annemarie Loof, the head of the medical aid organization's mission in the South Kivu region of the Democratic Republic of the Congo.
"Up to four armed men were involved at a time and homes and shops were looted," Loof added.
These alleged rapes come after reports from the United Nations that more than 200 people were systematically raped during rebel attacks in the summer of 2010 in the country.