The U.N. Security Council is grappling with a troubling question in the Democratic Republic of the Congo: How could U.N. peacekeepers not know about mass rapes taking place over a four-day period this summer?
The United Nations says it only found out about the atrocities more than a week after they ended, and from an international aid group.
U.S. Ambassador to the U.N. Susan Rice sounded exasperated after a Security Council meeting Thursday. She said she raised pointed questions about the rapes in eastern Congo.
"It was a disturbing briefing, both for what we learned and what we don't know still," Rice said.
U.N. Secretary General Ban Ki-moon has sent top officials to investigate, and ambassador Rice said she and her colleagues have started brainstorming about how to step up communications between remote Congolese villages and U.N. peacekeepers.
"In many instances, those procedures have worked; in this instance, clearly they did not," Rice said. "We need to know why and what mechanisms might be put in place to ensure that this type of horror is not repeated again and again."
The International Medical Corps -- which alerted the U.N. of the rapes -- first learned of security problems in the area through a U.N. email alert at the end of July, according to the humanitarian group's vice president, Rebecca Milner.
"There was a notice that there were armed perpetrators in the area that was distributed through the humanitarian listserv," Milner said.
Then, on Aug. 3, a local leader went to her organization to seek help, and when medical teams managed to get to the village in north Kivu province on Aug. 6, they heard stories about how several hundred rebels gang raped women over the course of four days.
"Often the rapes took place in front of the women's children and husbands, in front of their families," Milner said.
Since then, 156 women have received treatment, and Milner said the number of women coming forward is rising.
"The scale of this was really quite startling," Milner added. "In our recent records, we haven't dealt with this number before."
U.N. officials are still looking into who knew what and when. The top U.N. official in Congo, Roger Meece, said a patrol went through some villages in the area Aug. 2, but none of the villagers alerted the U.N. peacekeeping mission known as MONUSCO about the rapes.
In a video conference with reporters in New York, Meece speculated as to why this was the case: "Is it conceivable that local villagers were afraid of reprisals if they reported anything to MONUSCO? Possible. Is it conceivable that they were ashamed of what has happened in some form? That's possible."
Privately, U.N. officials also worry that villagers don't trust U.N. peacekeepers.
There are only 80 peacekeepers at the outpost that covers the area where the attack occurred, and officials describe it as a vast region with impassable roads and very limited cell phone coverage. Sexual violence is a widespread problem there, and will likely remain so as long as rebel movements are fighting, according to the U.N.'s outgoing humanitarian chief, John Holmes.
"The reality is that until these armed groups are dealt with once and for all, this risk is going to be there," Holmes said. "However well MONUSCO performs, they are not going to be able to stop every case of rape. They cannot be behind every bush."
The U.S. wants the United Nations to do a better job of at least knowing where civilians are at risk.