Sudan yesterday cancelled nine security and economic pacts with South Sudan, ending a brief interlude of harmonious relations after border clashes.
"We will stop all nine agreements, not only oil," the country's information minister, Ahmed Bilal Osman, said.
His announcement followed an order on Saturday from President Omar al-Bashir to shut the pipeline carrying South Sudanese crude for export.
The command came after Bashir warned the South over backing rebels, who analysts say humiliated the authorities with recent attacks.
South Sudan's government in Juba denies supporting insurgents in the north.
Osman said Sudan would allow the first oil from South Sudan that has reached Port Sudan to be exported. Chinese state-firm CNPC last week sold 1.2 million barrels of oil flowing from South Sudan's fields through a Sudanese pipeline to Sudan's export port.
"We won't confiscate this oil because it does not belong to South Sudan only but also to the [oil] companies, so it will be exported. We'll take our share," Osman told reporters.
Sudan and South Sudan - which split into two countries in 2011 after decades of war fuelled by oil and ethnicity - agreed in March to restart the crude flow following a 16-month shutdown triggered by an argument over transit fees and territory.
Crude had only just started to move through the pipelines in May, with the first cargoes sold last week for shipment from Port Sudan.
It can be very costly to close the pipelines, which can become blocked if the waxy oil stops halfway. The Chinese, Indian and Malaysian firms dominating the sector have been facing rising operating costs due to the shutdown since January 2012, oil sources say.
South Sudan would also have to shut down its entire oil production because it has no storage facilities.