Sudan's army says it has captured a rebel stronghold in the restive border state of Blue Nile.

Sudanese officials said Thursday the army has succeeded in pushing the rebels out of Kurmuk, a town located close to South Sudan, which broke away from Sudan in July. They said the town has been “totally liberated and secured” from forces loyal to the southern neighbor.

In addition to Blue Nile, Sudanese forces were engaged in operations against rebel movements in two other states — Southern Kordofan and Abyei, oil-rich regions on the border between the countries.

Blue Nile and Southern Kordofan were battlegrounds during Sudan's 21-year north-south civil war, and fighters in both states sided with the south.

Sudan and South Sudan have yet to settle disputes over borders and oil revenue, stemming from the South's independence. South Sudan has most of the oil production but needs Sudan's Red Sea export facilities.