The paramilitary Rapid Support Forces, at war with Sudan's regular army for over a year, said Thursday they had captured a key base near the border with South Sudan.
RSF fighters "successfully liberated the 92nd Brigade (base) in the strategic Miram area in West Kordofan state," the group said on social media site X.
In footage published online, fighters on armoured vehicles were seen celebrating outside what appeared to be the entrance to the Miram base, some 60 kilometres (40 miles) north of the border.
The RSF -- which has been accused of war crimes, crimes against humanity and ethnic cleansing -- is already in effective control of Sudan's borders with Chad, the Central African Republic and Libya.
The army did not immediately respond to an AFP request for comment on the claimed capture of the base, which lies in an oilfield district close to the disputed Abyei region of the border.
In May, the United Nations called on South Sudan to withdraw its forces from Abyei, warning of rising tensions in the region where it has peacekeepers deployed.
The war in Sudan, which began in April 2023, has dealt a heavy blow to its southern neighbour which is still picking up the pieces after a devastating civil war of its own.
In February, the rupture of a key Sudanese pipeline that delivers South Sudanese oil to the Red Sea coast threw the country's main source of revenue into jeopardy.
Refugees from South Sudan's 2013-18 civil war make up the great majority of the more than 700,000 civilians who have fled south since April 2023, according to UN figures.
The influx has placed a heavy burden on one of Africa's poorest countries.