A leading charity has warned that a new wave of violent conflict has displaced up to 35,000 children in Sudan's contested border region of Abyei.

Northern Sudanese tanks rolled into Abyei last weekend and forced residents to flee, igniting a conflict that many fear could escalate into civil war.

Both northern and Southern Sudan stake a claim to Abyei, a fertile grassland near several oil fields.

Save the Children's U.K. office says children who have been separated from their families since fighting broke out are at "grave risk" of being targeted for sexual and physical abuse or recruited into the armed conflict.

Save the Children said Sunday it's "desperately worried about those children currently beyond the reach of humanitarian assistance."