North Sudan's government has laid out proposals for resolving its dispute with the south over the oil-rich Abyei region.

North Sudanese forces occupied Abyei on May 21, prompting tens of thousands of residents to flee the area, and raising fears the north and south could return to civil war.

The northern government suggested setting up a rotating administration for the contested region. It also has called for replacing international peacekeepers in Abyei with an African force.

A top aide to U.S. President Barack Obama met with Sudanese leaders on Wednesday and voiced Mr. Obama's “deep concern” over the north's military presence in Abyei. The White House said Homeland Security and Counterterrorism advisor John Brennan urged a “rapid and peaceful resolution to the crisis.”

The north has previously rejected calls from the United States, United Nations, and south Sudan to remove its troops from Abyei.

South Sudan is set to declare independence July 9, after voting to split from the north in a January referendum.

Abyei was scheduled to vote the same day in January on whether to join the north or south, but the sides could not agree on who was eligible to vote.

An international monitoring group has accused North Sudan of committing war crimes in the region, saying northern troops are looting and destroying buildings in Abyei's main town.

The U.N. refugee agency said Tuesday that more than a third of the huts in Abyei have been burned down. It said most of the area's population has fled southward, and warned that insecurity is affecting the delivery of aid to the displaced.

On Tuesday, the African Union said North and South Sudan had agreed to create a demilitarized border zone, with joint patrols stretching the length of their 2200-kilometer-long boundary. Ethiopia has said it would consider sending peacekeepers to help monitor the border if both sides request it.

North and South Sudan fought a 21-year civil war that ended with a 2005 peace agreement.