The United Nations refugee agency says the number of people who have fled Sudan's disputed Abyei region has reached 100,000.

A spokeswoman for the U.N. High Commissioner for Refugees told VOA most of them are seeking refuge in Warrap state, south of Abyei.

U.N. officials believe many displaced persons are still hiding in the bush and desperately need food, water and other basic aid.

Many of the refugees began fleeing the north-south border region last month, after northern troops seized control of Abyei.

The south is preparing to declare independence from the north on July 9, and the two sides have not agreed on the future of the oil-rich region.

Khartoum has rejected calls by the U.N. Security Council to withdraw its forces.

Officials fear the renewed tensions could plunge Sudan into a new civil war.

North and south Sudan fought for 21 years before the conflict ended with a 2005 peace agreement.

On Monday, U.N. Mission in Sudan called on the north's armed forces to bring the looting in Abyei to a halt, release civilians in its custody, and allow unrestricted and safe access to people in need of humanitarian aid.