UNITED NATIONS, Nov. 5 (Xinhua) -- UN humanitarians said Wednesday that they are deeply alarmed over the reported increase in atrocities and abuse of civilians fleeing Sudan's El Fasher.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) said it has been receiving mounting reports of grave violations against civilians as fighting continues in Sudan's North Darfur state.

"Local volunteers have publicly reported executions, sexual violence, humiliation, extortion and attacks, among other systematic abuses, including on people fleeing the fighting following the Rapid Support Forces' capture of the state capital, El Fasher, last week," OCHA said.

The humanitarian office said analysis of satellite imagery revealed at least two mass graves near a mosque and the former children's hospital, as well as multiple sites showing signs of body disposal operations.

The UN Population Fund reported that women and girls faced rape, abduction and other extreme violence while fleeing El Fasher.

Local sources reported that about 1,300 people with gunshot wounds arrived in the town of Tawila, 40 kilometers from El Fasher, after being attacked as they escaped the city, said OCHA.

The International Organization for Migration (IOM) reported that as of Tuesday, nearly 82,000 people have fled El Fasher and surrounding areas since the city's fall on Oct. 26.

Tawila is the locality where most of those displaced from the state capital head to, and humanitarian needs in the area far exceed available resources, the IOM said.

The UN Refugee Agency (UNHCR) reported that Sudan's neighbor to the west, Chad, has become a critical refuge for those fleeing the Sudan conflict, hosting 1.4 million refugees, mainly from Darfur.

"With escalating violence in El Fasher, another major influx into Chad is anticipated, placing additional pressure on host communities," the UNHCR said.

Calling on the international community to scale up support to Chad's refugee response urgently, the UNHCR said "critical sectors such as health, water, sanitation and protection are under-resourced, leaving thousands without adequate support."

OCHA called again for an immediate cessation of hostilities in Sudan and for all parties to uphold their obligations under international humanitarian law, including the protection of civilians and the safe, unhindered passage of humanitarian workers and relief supplies to reach those in need. ■