Sudan has initiated a shutdown of the Heglig oil facility following drone attacks it blamed on the paramilitary Rapid Support Forces, according to a letter sent by its government to its South Sudanese neighbour and seen by Reuters.

Heglig, which lies along Sudan's southern border, houses the main processing facility for South Sudanese oil, which accounts for the majority of South Sudan's government revenues.

The 2023 outbreak of the war between the Sudanese army and the RSF has disrupted the flow of South Sudanese oil to Sudan, which before the conflict had been receiving between 100 000 and 150 000 barrels of oil per day for further exports.

The letter sent by Sudan's energy ministry to its South Sudanese counterparts cited drone attacks on August 26 and 30 as the cause for the shutdown.

"Such unprovoked attacks represent a serious threat to the stability of oil flows from South Sudan and we cannot in good faith continue to man the operation there," the letter, dated August 30, said.

As a result, Sudan had instructed the Sudanese companies operating in the area, 2B OPCO and PETCO to evacuate, and said the latter would not be able to meet its lifting schedule.

"Their continued operation despite ongoing attacks by the RSF will render them inoperable in the long run," the letter said.

South Sudanese officials and the two companies could not be immediately reached for comment.

The RSF did not respond to requests for comment.