The government in Khartoum says they will not stand by after an oil field was occupied by South Sudanese forces.
JUBA and TALODI, Sudan
Sudan's government vowed on Thursday to deal swiftly with South Sudan's occupation of an economically vital oil field near the border but the south said it would not pull out until the threat of attacks by the northern army had gone.
The stand-off follows clashes along the ill-defined border that have brought the former civil war foes closer to returning to full-blown conflict than at any time since South Sudan declared independence last year.
South Sudan seized the Heglig oil field on Tuesday, drawing international condemnation including rare criticism from the United States. Sudan has called the move a "blatant assault" on its sovereignty and demanded an immediate withdrawal.
Heglig, which the south claims as its own, is vital to the north's economy because the field there accounts for about half of the country's remaining 115,000 barrel-a-day oil output.
Ahmed Haroun, governor of Sudan's South Kordofan border state, said crude production had stopped in Heglig, but the army was "dealing with the situation".
"We hope we can finish that operation in hours ," he told reporters in the town of Talodi in South Kordofan, a state on the border with South Sudan where Khartoum is also battling insurgents who it alleges are aligned with Juba.
With the European Union voicing "deep concern" at the escalating conflict, the north said it was mobilizing its army to retake the Heglig field, which the South said it had seized to end attacks from Khartoum.
South Sudan's President Salva Kiir said the conflict could lead to war.
"I urge you to sensitize our people to the probability of a full-scale military aggression by the Republic of Sudan against the Republic of South Sudan," he told parliament, according to a transcript of the speech.