Most of the worst abuses have been committed by rebel groups, many of whom fled to Congo after taking part in the Rwandan genocide of the 1990s, she said.
"The atrocities perpetrated by these armed groups are of an unimaginable brutality that goes far beyond rape," she said in a statement. "Women are brutally gang raped, often in front of their families and communities. In numerous cases, male relatives are forced at gunpoint to rape their own daughters, mothers, or sisters."
The statement continued: "Frequently women are shot or stabbed in their genital organs, after they are raped. Women, who survived months of enslavement, told me that their tormentors had forced them to eat excrement or the human flesh of murdered relatives."
Saying the situation required immediate attention from Congo's government and the international community, Erturk reported that 4,500 cases of sexual violence had already been counted this year. The UN investigator said the actual number of attacks was probably much higher.
The Panzi hospital, a specialized institution in Bukavu near the Rwandan border, treats about 3,500 women a year suffering severe genital injuries resulting from atrocities, Erturk said.
The mineral-rich eastern reaches of Congo, bordering Uganda, Rwanda, and Burundi, are the most unstable in the country, and civilians are often killed as rival militias clash.
UN peacekeepers helped end a wider 1998-2002 war in Congo that engulfed six countries, and the nearly 18,000-strong force currently in Congo is the UN's largest peacekeeping operation.
While rebels commit most of the worst abuses, Erturk said, government forces and national police are responsible for nearly 20 percent of all cases of sexual violence reported.
Army units have deliberately targeted communities suspected of supporting militia groups "and pillage, gang rape, and, in some instances, murder civilians," she said.
