At least 26 people, including paramilitary troops were killed in an armed clashes in Sudan’s South Kordofan province, according to the authorities on  Wednesday.

It marked the third outbreak of violence this month that could derail the country’s transition to democracy.

The fighting poses a significant challenge to efforts by Sudan’s transitional government to end decades-long rebellions in some areas of the country.

Sudan is on a fragile path to democracy after a popular uprising led the military to overthrow former autocratic president Omar al-Bashir in April last year.

Deputy Chief of Staff of Sudan’s military Abdalla al-Bashir said that fighting took place this week between armed residents in a market in the city of Kadugli, the provincial capital of South Kordofan.

He further added that two dozen were dead in two days.

Al-Bashir said the dispute was over an arms sale and that it escalated in the past two days in the market and in some villages in Kadugli.

The city is located around 715 kilometres (444 miles) south of Sudan’s capital, Khartoum. Authorities imposed a round-the-clock curfew for three days to stabilize the situation, he said.

Brig. Gamal Ammer, spokesman for the paramilitary Rapid Support Forces, said at least nine soldiers were killed and at least 26 other people, including 10 civilians, were wounded in the clashes, which erupted Monday night.

Abdalla al-Bashir, who was in Kadugli on Wednesday, said the violence was not the result of tribal clashes but rather a dispute between individuals dating back to April when outlaws looted livestock in a village south of Kadugli.

He did not elaborate. He said an investigation was opened and that those involved would be prosecuted.

Mussa Mahmoud, the secretary general of the provincial government, blamed an outlawed group for the clashes. He also did not elaborate.

Last week, tribal clashes in the provinces of South Darfur and Kassala left at least three dozen people dead and dozens wounded.

The violence came as authorities struggle to fight the coronavirus pandemic. Sudan’s health care system has been weakened by decades of war and sanctions.

The country has more than 1,660 confirmed cases, including at least 80 deaths.

In 2013, at least hundreds of people were killed and up to 20,000 others had fled to UN bases in days of fierce fighting in South Sudan’s army after an alleged coup bid.

In 2015, Sudanese rebels had said that they killed 54 government soldiers and seized a strategic town in South Kordofan region, but the Sudanese army denied the matter.

(With inputs from agency)