Sudan has threatened to close its border with South Sudan – and cut off food aid unless the neighbour expels rebels who are allegedly taking refuge in its territory, the government told state media.
Khartoum regularly accuses its neighbour of backing insurgents in the Darfur, Blue Nile and South Kordofan regions that run along its southern border.
The two countries split in 2011 after decades of civil war fuelled by ethnic divides and disputes over oil. The border was closed after the 2011 split and was re-opened last January.
Speaking to state media on Sunday, Kamal Ismail, a minister of state in the foreign ministry, said that South Sudan had pledged to expel the militant groups within 21 days during a visit last month.
Khartoum would re-seal the border if its neighbor did not meet this promise, Ismail said.
The position of the border, particularly in the contested Abyei area, has been a constant source of tension, as has the legal status of southerners left living in the north and vice versa.