Mona Lisa lay on a hospital bed in Mekelle, the main city in war-torn northern Ethiopia, her body devastated but her defiance on display.

Named for the iconic painting, the 18-year-old Ethiopian high school graduate had survived an attempted rape that left her with seven gunshot wounds and an amputated arm. She wanted it to be known that she had resisted.

“This is ethnic cleansing,” she said. “Soldiers are targeting Tigrayan women to stop them giving birth to more Tigrayans.”

Her account is one of hundreds detailing abuses in Tigray, the mountainous region in northern Ethiopia where a grinding civil war has been accompanied by a parallel wave of atrocities including widespread sexual assault targeting women.

told the Security Council last week that more than 500 Ethiopian women have formally reported sexual violence in Tigray, although the actual toll is likely far higher, she added. In the city of Mekelle, health workers say new cases emerge every day.

The assaults have become a focus of growing international outrage about a conflict where the fighting is largely happening out of sight, in the mountains and the countryside. But evidence of atrocities against civilians — mass shootings, looting, sexual assault — is everywhere.

increasingly desperate pleas for international action on Ethiopia, led by senior United Nations and European Union officials, the pressure appears to be producing results. President Biden recently sent an envoy, Senator Chris Coons, Democrat of Delaware, to Ethiopia for talks with Ethiopia’s prime minister, Abiy Ahmed, that lasted five hours.

On Tuesday, addressing Ethiopia’s Parliament, Mr. Abiy publicly acknowledged that sexual assault had become an integral part of a war he once promised would be swift and bloodless.

said earlier this month.

The war started in November after Mr. Abiy accused the T.P.L.F. of attacking a major military base in a bid to overthrow his government. The T.P.L.F. ruled Ethiopia for nearly three decades until Mr. Abiy came to power in 2018, then retreated to its stronghold in Tigray where it began to openly defy the new prime minister’s authority.

In some ways, the bitter fight is driven by deeply rooted forces — longstanding land disputes, opposing visions over the future shape of Ethiopia, and a rivalry with Eritrea going back decades. But civilians, and particularly women, are bearing the brunt of the most disturbing violence.

Rocks, nails and other objects have been forced inside the bodies of women — and some men — during sexual assaults, according to health workers. Men have been forced to rape their own family members under threat of violence, Pramila Patten, the top U.N. official on sexual violence in conflict, said in January.

“Rape is being used as a weapon of war,” said Letay Tesfay of the Tigray Women’s Association, which runs a safe house for women in Mekelle. “What’s happening is unimaginable.”