|N African leaders are in Khartoum to calm fears about potential violent outcomes to the independence vote [AFP]
The leaders of Libya and Egypt have flown in to neighbouring Sudan to try to patch up disputes over a referendum on independence for south Sudan, underscoring growing regional concerns about the vote.
People from the south are widely expected to choose independence in the vote due to take place from January 9, but Egypt's President Hosni Mubarak and Libya's Muammar Gaddafi have both called in the past for the nation to remain united.
The leaders, whose countries share long, porous desert borders with Sudan, were due to meet Omar
Al-Bashir, the Sudanese president, and Salva Kiir, the leader of the semi-autonomous south.
On Monday, Al-Bashir also met with Mohamed Ould Abdel Aziz, the Mauritanian president.
Ahmed Aboul Gheit, the Egyptian foreign minister, told reporters in Cairo that Tuesday's meeting was designed to ensure that the referendum is held in a "climate of freedom, transparency and credibility, reflecting the will of the sons of the south" and that the south and north build strong ties.
He also said that the summit would review some of the outstanding issues between the two Sudanese sides.
Leaders of the north's ruling National Congress Party (NCP) and the main southern party, the Sudan People's Liberation Movement (SPLM), have talked for months about the location of their common border, how to split oil income and other issues.
The plebiscite was promised in a 2005 peace deal to end more than two decades of civil war between the mostly Muslim north and the oil-producing south, where most people follow traditional beliefs and Christianity.
Both Libya and Egypt view Sudan as their strategic backyard and would want to see the breakup of their southern neighbour to be peaceful and avoid any massive flow of refugees into their territory as a result of any renewed fighting.
While Libya sees Sudan as a vital piece of its Africa-focused foreign policy, there is much more at stake there for Egypt, the most populous Arab nation.
Sudan lies astride the middle reaches of the Nile, the primary source of water for mainly desert Egypt. The White Nile, one of the river's two main tributaries, runs through south Sudan.
Egypt fears an independent south Sudan may come under the influence of rival Nile basin nations like Ethiopia that have been complaining Egypt uses more than its fair share of the river's water.
"Guaranteeing our water needs and safeguarding our Nile resources are a central component of our vision for the future," Mubarak told his parliament on Sunday.
But there has been little public sign of progress. Both Sudanese sides have accused the other of building up troops, and analysts say disputes over preparations for the vote could reignite conflict, threatening the entire region's stability.
"They know the stability of Sudan will reflect positively on Libya and Egypt," Rabie Abdelati, a Sudanese information ministry official, told Reuters. "They are coming to smooth out the differences between the NCP and the SPLM."
Meanwhile on Tuesday, an internal UN document said the world body is planning for the possibility that 2.8 million people will be displaced in Sudan if fighting breaks out over the south's January independence referendum.
Just over two weeks remain before voters in Southern Sudan decide whether to remain with the Khartoum-based north.
Analysts say it is likely the south will secede and create the world's newest country.
If worst-case scenarios are played out, the UN plan anticipates an estimated 2.8 million internally displaced people within Sudan.
On Sunday, al-Bashir vowed to entrench strict Islamic Sharia law more deeply in the northern half of his country if the predominantly animist and Christian south votes to secede in the referendum.
His comments appear to reflect his anger at the strong likelihood that the south will vote overwhelmingly in favour of independence from the mainly Arab and Muslim north in the long-awaited referendum.
Al-Bashir is wanted on an international indictment for war crimes in the western Sudanese region of Darfur.
With only three weeks left before the vote, al-Bashir appears to be resigned to the secession of the south and also prepared to do away with key provisions of the 2005 peace accord that recognises Sudan's ethnic, religious and linguistic diversity.
The secession of the south, he said, would be like "losing a part of the homeland, but it will not be the end of the world."
"If the south breaks away, God forbid, the constitution will be amended to have Sharia as the main source of legislation, Islam the official religion of the state and Arabic the state's main language," said al-Bashir, who came to office in a 1989 military coup.
A full-fledged implementation of Sharia law in northern Sudan could create a new point of friction between south and north because hundreds of thousands of non-Muslim southerners live in the north and many of them are expected to stay there even if the south breaks away.
Currently, non-Muslims are exempt from prescribed Sharia punishments.
Al-Bashir's comments could be an attempt to cover up his failure to keep Sudan united and intact, according to Fayez Selik, a Sudanese analyst.
"Al-Bashir is saying to the north: we lost the south but we won Sharia," Selik, editor of the pro-south daily Ajras al-Hurriya, or Freedom Bells, said.
Sharia law was first introduced in Sudan in 1983 and it fuelled a southern insurgency in its early years. Authorities soon relaxed implementation, but began to be strictly apply it again when al-Bashir came to power. It was relaxed again after the 2005 peace accord.