Nineteen people, one of them a humanitarian worker, were killed in ethnic clashes over the weekend in the Abyei region straddling the border between Sudan and South Sudan and claimed by both, local authorities said.
Violence is common in the oil-rich territory, with 54 people killed last week alone, including two UN peacekeepers.
Another 64 people were injured in fighting last week between two tribes of the main ethnic Dinka -- the Abyei-based Ngok and their Twic rivals from the neighbouring state of Warrap in South Sudan.
Both sides have sought to press their own claim since South Sudan gained independence in 2011, whereupon the disputed Abyei area was placed under UN protection.
"The attacks on civilians culminated in the loss of life, setting the market ablaze, property looting and raiding livestock," the Abyei Administrative Authority (AAA) said.
The AAA said the fighting at the weekend "contravenes the presidential order that calls for a peaceful settlement of the communal conflict between Ngok Dinka and Twic of the Warrap State".
The Authority said one person was killed and another three abducted on Saturday.
It said that on Sunday 18 people, including "four women and three children, as well as a humanitarian aid worker from Doctors without Borders," were killed in another attack by Twic youths and armed militiamen.
The conflict between the tribes began in 2022 over land claims in an area located on the southern edge of Abyei and the state of Warrap.
In January, South Sudanese President Salva Kiir called for a ceasefire, months after at least 32 people were killed in November clashes between the two groups.