Paramilitaries from Sudan's Rapid Support Forces (RSF) have advanced on the southeastern trading hub of Sennar as they push to expand territorial gains more than 14 months into a war with the army, residents and officials said on Wednesday.

Families fled the city on the banks of the Blue Nile after hearing the sound of fighting on Tuesday evening, locals said.

"We can hear artillery and heavy gunfire. I left Sennar with my family and we're heading south because I'm scared for my children," 49-year-old Nazik Ahmed told Reuters by phone.

U.N. agencies say around 10 million people have fled their homes across Sudan since the army and RSF fell out over a planned integration of their forces and started fighting in the capital Khartoum in April last year.

The RSF has since taken over most of Khartoum, the central farming state Gezira and the vast western Darfur region, as well as many parts of the Kordofan regions to the south.

In Sennar, south of Gezira, many took refuge in surrounding villages, locals said. Fighting raged through the evening then appeared to die down overnight, they added.

The state's army-led security committee said the military and allied fighters had destroyed seven RSF vehicles that had approached the city and fired rockets.

Reuters was not able to confirm the accounts of fighting.

In a video posted online on Wednesday, RSF soldiers said they would take over the city soon but called on residents to stay.

ATTACKS, ACCUSATIONS

The RSF has been making advances into the state for weeks, locals say. On Monday and Tuesday, it clashed with the army in the strategic Jebel Moya area, and said it now controlled the area in a video posted on X on Tuesday.

It circulated another video on Tuesday showing vehicles, mostly motorcycles driving through an area on the northern edge of Sennar.

Residents say the RSF has looted homes, raped women and girls, and killed civilians arbitrarily in areas it has entered. The United States has also accused it of war crimes as well as crimes against humanity and ethnic cleansing. The army, which has carried out a vast air strike campaign has also been accused of war crimes by the United States.

Both sides deny the accusations.

Fighting, including in the capital Khartoum, has intensified before the country enters its summer rainy season which makes movement across the country difficult.

Aid agencies have warned the rain will impede crucial deliveries of food and other supplies, which have also been held up by bureaucratic blockages and risk of looting.

The RSF earlier this week took control of al-Fula, the capital of West Kordofan state, which is close to oil fields and pipelines.

Fighting has also continued in the Darfur city of al-Fashir, where the RSF has imposed a months-long siege as it fights the army and allied forces inside the city.

Medical aid agency MSF said the last remaining hospital there with surgical capacity was attacked by the RSF on Friday. Local emergency response room volunteers say other medical facilities have also come under fire.