"Around 25 citizens, most of them women and children, have died in a boat sinking" while crossing the Blue Nile River in the southeastern state of Sennar, the local resistance committee said in a statement.

The committee is one of hundreds across Sudan that used to organise pro-democracy protests and have coordinated frontline aid since the war between the army and the paramilitary Rapid Support Forces (RSF) began last year.

"Entire families perished" in the accident, they said, while fleeing the RSF's recent advance through Sennar.

On Saturday, the RSF announced they had captured the military base in Sinja, the capital of Sennar state, where over half a million people had sought shelter from the war.

Witnesses also reported the RSF sweeping through neighbouring villages, pushing residents to flee in small wooden boats across the Nile.

At least 55,000 people fled Sinja alone within a three day period, the United Nations said Monday.

Local authorities in neighbouring Gedaref state estimated on Thursday that some 120,000 displaced people had arrived this week. The state's health minister Ahmed al-Amin Adam said 90,000 had been officially registered.

Over 10 million people are currently displaced across Sudan, in what the UN calls the world's worst displacement crisis.

Sudan has been gripped by war since April 2023, when fighting erupted between forces loyal to army chief Abdel Fattah al-Burhan and the RSF led by his former deputy Mohamed Hamdan Daglo.

The conflict in the country of 48 million has killed tens of thousands, with some estimates putting the death toll as high as 150,000, according to the United States envoy to Sudan, Tom Perriello.