U.S. Army Brig. Gen. Christopher K. Haas, commander of U.S. Special Operations Command Africa, returns the salute of Lieutenant Colonel Pepe Tongawa in Kisangani, Democratic Republic of Congo. (Courtesy of U.S. Air Force)

A Congolese army battalion that received its formative training from the U.S. military went on to commit mass rapes and other atrocities last year, a U.N. investigation has found.

Members of the 391st Commando Battalion, a unit created in 2010 with extensive support from the U.S. government, joined with other Congolese soldiers to rape 97 women and 33 girls as they fled a rebel advance in eastern Congo in November, according to the United Nations.

U.S. Special Operations forces had spent eight months training the 750-member battalion in a bid to professionalize Congo’s ragtag military, which has a long history of rights abuses, including raping and killing civilians. The training program, dubbed Operation Olympic Chase, was led by the State Department and the U.S. Africa Command, which oversees military operations on the continent.

Two years later, members of the battalion joined other Congolese soldiers to rape and rob scores of civilians in Minova, a town in eastern Congo, according to an investigative report released last week by the U.N. Joint Human Rights Office. The attacks occurred as Congolese forces were chased out of Goma, a key provincial capital, by a rebel group known as M23.

On Monday, the State Department acknowledged that some U.S.-trained soldiers “may be implicated in these rapes,” according to an e-mailed statement from a spokeswoman, Hilary Renner. “We condemn these crimes unequivocally and call for a full and credible investigation” by the Congolese government, she added.

Officials with the Africa Command, which is headquartered in Stuttgart, Germany, declined to comment.

The U.N. findings represent another setback in the U.S. military’s efforts to train and equip troops in Third World countries, many of which have poor human rights records.

In March 2012, a Malian army captain who had received extensive training in the United States led a coup that toppled his country’s democratically elected president. In the aftermath, France and neighboring African countries intervened militarily — with U.S. aid — to prevent Islamist fighters from taking over much of the country.

The Pentagon is ramping up its training in irregular warfare and counterterrorism with friendly countries as part of a broader strategy to combat extremist groups and stabilize war-torn regions. At any given time, U.S. Special Operations forces are deployed on training or liaison missions to as many as 80 countries.

U.S. law requires that individual foreign troops be vetted for human rights abuses before they can receive training. But some U.S. military leaders have said that those rules can be too restrictive and prevent Special Operations forces from training units that need the most help.

The U.N. report accused the Congolese military of “gross human rights violations” and documented 135 cases of sexual assault by Congolese soldiers in Minova. The report also accused M23 rebels of sexually assaulting 59 civilians in Minova.

The leadership of the Congolese armed forces is investigating the allegations. The commander and deputy commander of the 391st Battalion are among 12 officers who have been suspended, according to the United Nations.

While Operation Olympic Chase was underway in 2010, State Department and U.S. military officials said they were fully aware of the Congolese military’s troubled history. The training program, they said, emphasized respect for human rights and the need to protect civilians, particularly from sexual violence.

“You have enhanced your moral understanding of how a professional military operates effectively within a democratic society to provide security, to protect the civilian population and to contribute to greater stability,” Samuel Laeuchli, the ranking U.S. diplomat in the Congo at the time, said in a speech at the 391st Battalion’s graduation.

Thierry Vircoulon, Central Africa project director for the International Crisis Group, said the U.S. government underestimated what it would take to reform the Congolese armed forces.

“The state of the army in itself is a disaster, so you train people and you send them back to a dysfunctional army,” he said. “You are trained, but you still have a very low wage, no logistics, a very poor command system and no sense of belonging and cohesion because the Congolese army is still a patchwork of very different groups. Even if you’re trained, at the end of the day, you’re still an hungry and unpaid soldier.”

A senior U.S. official familiar with the training program said the Obama administration was aware of the risks but faced “tremendous political pressure to do something for Congo.”

“There were a lot of criticisms at the time that this would just make them [the troops] better able to oppress their own people,” the official said, speaking on the condition of anonymity because he was not authorized to talk to the media. “It’s one of those political judgment calls. . . . We bent over backwards to make this investment and to avoid the pitfalls and to really do it right.”