Large North Sudan army build-up
Khartoum - Satellite images showed the north Sudanese military massing in the Southern Kordofan border state, a monitor said, and rebels in Darfur accused Khartoum of attacking them with military vehicles and warplanes on Sunday.
Southern Kordofan, on the ill-defined border with the south, is among several flashpoints as Sudan's south prepares to secede on July 9, a move analysts say could embolden rebels in other parts of the country. The north's army is also battling armed groups in the western region of Darfur.
The Satellite Sentinel Project (SSP), which monitors Sudan, said new imagery from Friday showed the Sudan Armed Forces (SAF) controlled Kadugli, capital of Southern Kordofan, and that thousands of civilians had been displaced.
The images "show a massing of SAF artillery, light vehicles and heavy transports of the kinds used to carry tanks, troops, and munitions", it said.
Fighting between the northern military and southern-aligned groups has spread across the north-run oil state since June 5. Tens of thousands have fled, according to the United Nations.
Northern military spokesperson Al-Sawarmi Khaled said the army was not planning any escalation in Southern Kordofan but would continue to fight to end an armed rebellion, saying: "We are now fighting harder to control all the area in Southern Kordofan."
Southern Kordofan, the main oil-producing state that will be left in the north after the south secedes, is home to thousands of fighters who fought against Khartoum during the last civil war, many of them from the Nuba mountains region.
In Darfur, the Sudanese army confirmed it had clashed with rebels in the mountainous Jabel Marra region, but said it had not used aircraft and the fighting had not displaced civilians.
The United Nations has called on Khartoum to open up airspace above Southern Kordofan and said a campaign of aerial bombardment there has caused "huge suffering" to civilians.