CAIRO -- Tribal clashes between Arabs and non-Arabs in Sudan's West Darfur province killed around 130 people over the weekend, including children and women, doctors and an aid worker said Monday. Authorities In South Darfur, meanwhile, reported dozens of casualties from ethnic fighting in that province.

The latest violence in West Darfur grew out of a fistfight Friday in a camp for displaced people in Genena, the provincial capital, and then escalated, lasting until Sunday.

The clashes, between members of the Arab Rizeigat tribe and the non-Arab Massalit tribe, displaced at least 50,000 people, according to the United Nations.

The doctors' committee in the province said the clashes killed at least 129 people and wounded 189 others, including newborn babies. Among the dead was a U.S. citizen, Saeed Baraka, from Atlanta, who was visiting family in Darfur.

The committee, which called the violence “unprecedented,” said the casualty toll was likely to increase.

“The scale of the crisis in West Darfur is unimaginable. The transitional government should bear its responsibilities and declare the province a disaster area,” it said.

The committee is part of the Sudanese Professionals Association, which spearheaded a popular uprising that eventually led to the military's ouster of longtime autocratic president Omar al-Bashir in April 2019.

Adam Regal, a spokesman for a local organization that helps run refugee camps in Darfur, said families started to bury their dead after the clashes subsided. However, he warned of the potential for renewed fighting.

The U.N. Office for the Coordination of Humanitarian Affairs, said initial estimates show that at least 50,000 people were displaced because of the violence. It said the displaced families have taken shelter in schools and government buildings. OCHA said there was an “urgent need” for protection, shelter and food.

Authorities imposed a 24-hour curfew in all of West Darfur province and authorized military and police to use “all necessary force” to regain order. The central government in Khartoum also deployed security reinforcements.

In South Darfur, deadly tribal clashes between the Rizeigat and non-Arab Falata tribe resumed Monday, leaving dozens of casualties, Gov. Mousa Mahdi said.

The violence in al-Twaiyel village, 85 kilometres (53 miles) south of Nyala, the provincial capital, was sparked by the killing of a shepherd, he said.

He neither gave further details nor said how many were killed. Local media reported, however, that the violence left at least 60 dead and 40 wounded.

Mahdi said more troops from the province and neighbouring East Darfur province were deployed to the village.

The clashes threaten to derail Sudan's fragile transition to democracy. A military-civilian government has been in power since April 2019, and has struggled to end the country's decades-long civil wars and overcome crippling economic conditions.

The violence in Darfur came two weeks after the U.N. Security Council ended the joint U.N.-African Union peacekeeping force's mandate in the region. The UNAMID force, established in 2007, was the first joint U.N.-AU peacekeeping operation. It was replaced with a much smaller, political mission known as the United Nations Integrated Transition Assistance Mission in Sudan, or UNITAMS.

Mohammed Osman, a Sudan researcher at Human Rights Watch, said the tribal violence in Darfur is an example of why many displaced people protested the end of UNAMID.

“As UNITAMS now is in charge, the (U.N. Security Council) and international community should make sure that the new mission is well positioned to fully discharge its mandate, in particular on protection of civilians, monitoring and reporting on human rights abuses,” he said.

The government and the Sudan Revolutionary Front, a coalition of several armed groups, late last year formed a 12,000-strong Civilian Protection Force to Darfur, according a peace deal they reached in 2020.

The Darfur conflict began in 2003 when ethnic Africans rebelled, accusing the Arab-dominated government in Khartoum of discrimination. The government was accused of retaliating by arming local nomadic Arab tribes and unleashing the militias known as janjaweed on civilians - a charge it denies.