Sudanese President Omar al-Bashir is threatening to close a pipeline carrying oil from South Sudan to the north, saying the south is supporting rebels.
Mr. Bashir said in a televised speech Monday that Sudan will close the pipeline if South Sudan gives any support to rebels in the border areas of South Kordofan and Blue Nile, and in Sudan's troubled western Darfur region.
The president, flanked by military officials, spoke after the army said it had retaken the town of Abu Kershola from rebels in South Kordofan.
Sudan and South Sudan agreed to resume cross-border oil flows in March, but tensions between the long-term foes have recently increased.
Rebels attacked towns in North Kordofan and South Kordofan in April. Sudan says the rebels are receiving support from the government of South Sudan, a charge the south denies.
The two countries have been at odds since South Sudan won independence from the north in 2011, after decades of civil war.
Their armies clashed along the border last year amid escalating disputes over oil pipeline fees, border demarcation, and which side controls revenue-producing oil fields.
The oil pipelines between the two countries were shut down for more than a year because of what the south considered excessive fees to use northern pipelines.