Washington - The United States said on Wednesday it was "gravely disturbed" about the mass rape of women in a remote area of the Democratic Republic of Congo last month.
"We strongly condemn these severe human rights abuses," State Department spokesperson Victoria Nuland said in a statement, two days after medics reported that nearly 250 women were raped in DRC in June.
Nuland said US officials were working with Congolese authorities, local and international organisations and the United Nations "to gather the information needed to swiftly bring the perpetrators to justice".
"The United States has repeatedly condemned the epidemic of sexual violence in conflict zones around the world and continues to speak out strongly on this issue," she said.
"The United States is committed to working with the DRC and we urge the government to fully investigate, arrest, and prosecute those found responsible for these attacks."
Some 248 women said they were raped by soldiers in DRC's Sud-Kivu province last month, according to local medical reports, in a region the United Nations has called the world's "rape capital."
A hospital doctor in Nakiele told AFP that 121 local women reported being the victim of rape on the night of June 11 to 12.
The previous night, 55 women reported being violated in nearby Abala, a nurse said, while another health worker said 72 women in the village of Kanguli said they were also raped that night.
Nakiele village chief Losema Etamo Ngoma told AFP that the rapes and looting were committed by at least 150 armed men under the command of national army colonel Nyiragire Kulimushi, also known as "Kifaru".
Kulimushi, who fled a military base south of Nakiele on June 8, is a former member of the Mai Mai tribal militia which integrated into the national army in 2009 following a peace agreement with Kinshasa.
Government spokesperson Lambert Mende said forces were actively looking for Kulimushi and that a special tribunal would be set up to look into the case.
The United Nations, rights groups and foreign governments have long complained about impunity for heinous crimes committed by soldiers in DRC.
Earlier on Wednesday a UN probe found that three groups of armed militia could have committed crimes against humanity when they raped at least 387 people in the DRC in 2010.
Margot Wallstrom, the UN's special representative on combating sexual violence in conflict, has in the past called DRC the "rape capital" of the world.