Sudan’s oil ministry on Tuesday formally told oil companies to block the export flow of South Sudanese crude, following an order from President Omar al-Bashir.

Sudan's oil ministry on Tuesday formally told oil companies to block the export flow of South Sudanese crude, following an order from President Omar al-Bashir.

Oil Minister Awad Ahmad al-Jaz presented the written directive in a meeting Tuesday with senior executives of the GNPOC joint operating company and Petrodar, the ministry said in a statement.

It orders them "to stop the process of transportation and exporting South Sudanese oil within 60 days starting from Sunday June 9", the ministry said.

On Sunday Khartoum froze nine security and economic pacts with South Sudan, including a deal to restore economically vital oil shipments through the Red Sea export terminal.

South Sudanese President Salva Kiir has said he would refer oil arguments with neighboring Sudan to African Union mediators, vowing not to take the country back to war.

Speaking on Monday, he said Sudan’s President Bashir was mobilizing for war, something he would not inflict on South Sudan if it could be avoided.

“The people of South Sudan should remain calm and patient as we work with the African Union to resolve this impasse with Sudan,” Kiir told reporters, while condemning the “aggressive attitude” of Khartoum.

But the Khartoum government said it remained committed to good relations if the South's government in Juba ended support for rebels on Sudanese soil.