The governor of Sudan's embattled Southern Kordofan region says his government is willing to find a negotiated end to fighting in the oil-rich area.

Ahmed Haroun said on Tuesday that Sudan is “committed to peace and dialogue,” but that armed groups are prolonging the battle by coordinating attacks with rebels from the nearby Darfur region.

The United Nations says an estimated 73,000 people have been displaced by the fighting in Southern Kordofan. Fighting between Khartoum's army and pro-southern elements broke out in the area on June 5. Activists say Sudan's military is targeting the state's ethnic Nuba people, many of whom backed the south during a 21-year civil war.

Separately, rebels in Darfur took up arms against the government in 2003, accusing Khartoum of neglecting their region.

Meanwhile, Haroun rejected claims by aid organizations who say that Sudan is restricting access to humanitarian agencies in Southern Kordofan.

On Wednesday, international advocacy group Human Rights Watch called on the United Nations to ensure international monitoring in the area to “prevent further atrocities.”

The United Nations says there is “strong evidence” atrocities are being carried out by Sudanese forces in the Southern Kordofan area.

In a statement last week, U.N. human rights experts cited “credible reports” of ongoing mass killings, arbitrary detentions, kidnappings, aerial bombardment and attacks on churches.

The United States has also said it is “deeply concerned” about “alarming and credible” reports of violence by Sudanese forces and its allies. U.S. Ambassador to the U.N. Susan Rice said last week the reports include “acts of extreme cruelty” against civilians.

Both statements said if the allegations are proven true, the acts could amount to crimes against humanity.

A U.S. satellite monitoring group, the Satellite Sentinel Project, released images earlier this month of three excavated areas in Southern Kordofan that the groups suspects are mass graves.

Sudanese officials have characterized the fighting in Southern Kordofan as a rebellion.