Fighting rages on Sudan-S Sudan border
Bentiu - Fierce fighting raged on Wednesday as Sudanese warplanes bombed contested regions on the border with South Sudan, the second day of violence in the oil-rich region.
South Sudanese troops held positions in the disputed Heglig oil field, seized on Tuesday from Khartoum's troops, said Mac Paul, deputy director of South Sudan's military intelligence.
South Sudan's armed forces the "SPLA are holding their positions in Heglig, and the bombardment continues... there was bombing all night long", Paul told AFP in the capital of South Sudan's frontline Unity state.
Several air strikes by Sudanese Antonov airplanes and fighter jets were reported at least 50km deep inside South Sudan, although officials had no immediate reports of casualties.
On Tuesday, an AFP correspondent on the South Sudanese frontline heard heavy artillery shelling and multiple airstrikes for around an hour, with one bomb dropped by aircraft landing less than a kilometre away.
Large South Sudanese troops movements were seen close to the frontier, with convoys heading up to the frontline near Heglig, an area Juba claims but which makes up a key part of Khartoum's oil production.
The clashes follow border fighting that erupted last month between the neighbours, the most serious unrest since Juba's independence last July, and which prompted international fears of a return to all-out war.
When South Sudan separated, it took three quarters of oil production, but it still needs the north's pipeline and port to export it.
The two sides have been unable to resolve a dispute over fees for the South's use of the infrastructure, which led Juba in January to shut crude production after Khartoum began seizing Southern oil in lieu of compensation.
Since then there were moves towards warmer relations, but analysts said hardliners in Khartoum and the South opposed a rapprochement and that fighting over Heglig may be an effort to sabotage the improved ties.
In last month's clashes, Southern troops briefly held Heglig before retreating, with Khartoum claiming to have driven them back in a counter-attack.
Khartoum has vowed to react with "all means" against a three-pronged attack it said South Sudanese forces had now launched against Sudan's South Kordofan state, including the Heglig oil field.
A statement on Khartoum's official SUNA news agency warned of "destruction" in South Sudan.
Khartoum also claimed Southern forces were backed by rebel groups in Sudan.
It did not specify which group, but guerrilla fighters from the Sudan People's Liberation Movement-North (SPLM-N) are battling government troops in South Kordofan.
Senior officials met in African Union-mediated crisis talks last week in the Ethiopian capital, but failed to sign an agreement on security, while negotiations on oil, a key driver of the conflict, are stalled.
Hundreds of thousands of citizens of each nation living in the territory of the other country are facing uncertain futures after a deadline requiring them to formalise their status expired at the weekend.
Over 370 000 Southerners have returned from Sudan since October 2010, but an estimated 500 000 remain in the north, while tens of thousands of Sudanese are believed to live in the South.