Both the SAF and SPLA will safeguard the flow of crude oil after the referendum, regardless of the outcome [EPA]

The Sudan Armed Forces (SAF), the Khartoum-based government's army, and its former enemy, the Sudan People's Liberation Army (SPLA) of south Sudan, have signed an agreement to secure the flow of crude oil from Sudanese oil fields, irrespective of the outcome of the upcoming referendum on south Sudan self-determination.

Al Jazeera's Mohamed al-Baggali, reporting from Sudan on Tuesday, said the agreement coincided with growing fears among oil companies over the post-referendum violence in Sudan.

The January 9 independence referendum in southern Sudan is a key element of the 2005 peace deal which ended a two-decade-long civil war between the north and south that killed around two million people.

Under the deal, known as the Comprehensive Peace Agreement, the south formed its own government, which has limited autonomy and in which the north has a small representation. South Sudan is nominally represented in the government of national unity, which is led by the Khartoum-based National Congress Party.

The oil treaty calls for joint military units between the SAF and the SPLA to safeguard the oil fields in the south up to July 2011. This will be based on a political arrangement to be reached after announcing the referendum results.

Mass resignations

The uncertainty that shrouds the future of the southern district has triggered mass resignations by oil workers as a precaution against possible violence related to the vote.

"We reaffirm to those working in those companies, as cited by the content of this agreement, the full commitment of the Sudanese federal government and the government of south Sudan to provide security and safety to them and to their activities", Ali Osman Taha, the Sudanese vice-president, said.

Sudan produces around 500,000 barrels of crude oil a day, by which the south Sudan government is sustained, while north Sudan gets more than half of its annual revenue.

Garang Deng, the south Sudan oil minister, said: "We hope that crude oil will keep flowing in case of unity or secession. This is because by benefiting from oil, we have improved the living conditions of the Sudanese people up to a certain level, both in north and south Sudan."

"In case the oil flow was interrupted, the living conditions of the people will begin to deteriorate," Garang added.

Uganda 'destabilising'

Meanwhile, the government of Sudan has accused neighbouring Uganda of supporting rebel groups in the Darfur region.

On Monday, Abdul Raheem Mohamed Hussein, the Sudanese defence minister, told Al Jazeera that Uganda's role in Sudan is "destabilising" and will have negatives consequences throughout east Africa.

"There is Ugandan intentional intervention against the security and stability of Sudan. This will have a large effect on the security and stability of the whole region," the defence minister said.

The accusations were triggered by leaks to the local Sudanese media and have created diplomatic tension between the two countries.

In November, Betty Akech Okullu, Uganda's ambassador to Sudan, was twice summoned by the Sudanese foreign minister over allegations that Yoweri Museveni, the Ugandan president, promised support to a Darfur rebel group, the Justice and Equality Movement (JEM).