By Aaron Maasho and Alex Dziadosz
ADDIS ABABA/KHARTOUM (Reuters) - The warring parties in Sudan's Southern Kordofan border state have agreed hostilities should cease and that talks should start, former South African President Thabo Mbeki said on Thursday.
Fighting between the northern military and southern-aligned armed groups broke out in Southern Kordofan on June 5 and has escalated to include artillery and warplanes. Over 60,000 people are believed to have fled the fighting, the United Nations said.
Both President Barack Obama and U.N. Secretary-General Ban Ki-moon have called for an immediate ceasefire in the north-run oil state, where humanitarian groups fear a mounting death toll.
The south due to become a separate country on July 9 and a raft of issues remain unresolved between the two sides, including where to draw the common boundary.
"Both sides have agreed that there should be a cessation of hostilities, and that negotiations should begin immediately. They've said they will discuss on certain modalities. The details can only be done within those negotiations," Mbeki told reporters in Addis Ababa after visiting Southern Kordofan.
Mbeki, who has been helping guide talks between north and south ahead of secession, said he and other officials would begin planning "full-fledged negotiations" between the Sudanese government and representatives of Southern Kordofan.
He did not give a time frame for when any ceasefire would go into effect. Earlier on Thursday Sudan's army said it would continue fighting against southern-aligned groups in Southern Kordofan to end what it calls an armed rebellion.
"We are continuing our military operations in the mountains around Kadugli up to this moment, until the rebellion stops," northern military spokesman Al-Sawarmi Khaled told reporters in Khartoum.
The United Nations urged north Sudan's military to open up airspace over Southern Kordofan, saying a six-day closure was endangering its aid operations there.
"The ongoing closure of the airspace in Southern Kordofan by SAF (Sudanese Armed Forces) is dangerously hampering our humanitarian operations as thousands of internally displaced persons are in urgent need of emergency assistance," U.N. Mission in Sudan spokesman Kouider Zerrouk said.
"It is vital that the government of Sudan acts immediately to ensure access to all airspace by U.N. flights to alleviate the growing suffering of those most affected by conflict."
The London-based group Save the Children said in a statement 30,000 of the displaced were children "at risk of being separated from their families, traumatized and abused."
Northern spokesman Khaled dismissed charges the army was putting civilians in danger, saying its role was to help them.
Southerners voted to secede in a January referendum that was promised in a deal in 2005 that ended decades of civil war.
Many of the fighters in Southern Kordofan are still referred to as part of the south's army as a legacy of that conflict, though the southern military says they are no longer part of its forces.
Officials in the south's dominant party have said the fighting erupted after the northern army tried to disarm fighters there, while northern officials have accused southern-aligned groups of starting the fighting.
The government in Khartoum stands to lose around a third of its territory and up to three quarters of its oil reserves when Africa's largest country becomes two states, but most of the terminals, pipelines and refineries are in the north.
The northern government's oil minister said earlier that north Sudan have agreed to accept transit fees from the south to export southern oil after July 9 but the two sides had yet to agree a price.
(Additional reporting by Khaled Abdelaziz; Writing by Alex Dziadosz; editing by Tim Pearce)