The United Nations food agency says thousands of people are crossing the border into the central African nation of Chad from neighboring Sudan to escape the nearly three-month-old violence that the world body's humanitarian chief has described as a civil war "of the most brutal kind."

The World Food Programme said in a statement Tuesday that 20,000 people from Sudan's Darfur region have arrived in the small Chadian border town of Adre in the last week alone. The agency said many of the people arriving from Darfur are seriously wounded amid reports that fleeing civilians are being deliberately targeted "with an increasing ethnic dimension to the violence."

The WFP statement says it estimates that about 10% of children crossing from Darfur into Chad are malnourished.

"People are running across the border, wounded, scared, with only their children in their hands and the clothes on their backs," said Pierre Honnorat, the WFP's country director in Chad. "They need safety, security, and humanitarian assistance."

The WFP says its relief efforts along the Chad-Sudan border have become increasingly challenging due to the annual rainy season. It has deployed two all-terrain vehicles that can each carry up to 1,200 kilograms of food and can cross multiple "wadis," or large gullies filled with rainwater.

More than 230,000 refugees and 38,000 returnees have crossed into Chad from Sudan since fighting began in April between the Sudanese military and the paramilitary Rapid Support Forces after months of rising tension over the country's political future and plans to integrate the RSF into the national army.