President Omar al-Bashir said on Sunday that northern Sudan will reinforce its Islamic laws after a January referendum which is expected to grant independence to the south.

On the same day, US President Barack Obama has written to regional leaders to rally support for a peaceful and timely referendum on the independence of south Sudan.

"If south Sudan secedes, we'll change the constitution. There will be no question of cultural or ethnic diversity. Sharia will be the only source of the constitution, and Arabic the only official language," he said in a speech on national television.

Bashir is wanted by the International Criminal Court for genocide, war crimes and crimes against humanity for atrocities in Sudan’s Darfur region.

Southerners are set to vote in a referendum on January 9th on whether to remain united with the north or break away and form their own country.

The vote is a key plank of the 2005 Comprehensive Peace Agreement between the mainly Muslim north and predominantly Christian south that put an end to more than two decades of civil war.  Analysts are predicting that the southerners will opt for independence, and senior officials in Khartoum are even beginning to accept the idea of the split.

An aide to Bashir admitted on Thursday that south Sudan would probably choose secession because efforts aimed at promoting unity had failed.

"Despite our work for unity, we should not deceive ourselves or cling to dreams. We should rely on the facts on the ground," the official SUNA news agency quoted Nafie Ali Nafie as saying. 

"After the secession of the south, we could see the north radicalise and the creation of a Muslim caliphate," one foreign official said on condition of anonymity.

After the civil war, Bashir's National Congress Party (NCP) and the former southern rebel Sudan People's Liberation Movement (SPLM) agreed on an interim constitution valid until July 2011.

The constitution recognises the "multi-ethnic," "multi-cultural" and "multi-faith" status of the Sudanese state, and is based on both sharia, or Islamic law, and the "consensus" of the population.

It also recognises Arabic and English as the two official languages of Africa's largest country, which was formerly under British and Egyptian rule.

Obama rallies African leaders to push for calm in Sudan

Obama has made Sudan a foreign policy priority and pushed Khartoum on both the referendum and the ongoing crisis in Darfur amid growing violence in the south.

"We believe that an on-time referendum is the best means of preventing the resumption of a full-scale war between northern and southern Sudan," White House National Security Council spokesman Mike Hammer said.

"Over the past four months, the administration has redoubled our efforts to support referendum preparations and peace negotiations between the two parties."

He said Obama wrote to a number of African leaders as part of an "ongoing aggressive diplomatic effort with the parties in Sudan and with its neighbors reflecting our intense interest in having a successful referendum."

The letter was sent to leaders in Chad, Egypt, Ethiopia, Kenya, Libya, Nigeria, Rwanda, South Africa, Uganda and the African Union, a US official said.

Britain's Foreign Secretary William Hague on Sunday put Sudan and Lebanon into the same bracket as potential areas of renewed conflict in the Arab world.

They were the "two areas in January that are most obvious at this stage to watch for a political crisis or an outbreak of violence," Hague told Britain's Sky News television.

Ocampo on Bashir diverting funds to the UK: Wikileaks

Meanwhile, US diplomatic documents revealed by Wikileaks on Saturday said that Bashir siphoned off nine billion dollars (6.79 billion euros) of oil money into British bank accounts.

A senior official in Bashir's ruling National Congress Party (NCP) denied the claim.

The document quotes ICC Chief Prosecutor Luis Moreno Ocampo as saying that US officials should go public with the allegations about Bashir in order to turn Sudanese public opinion against him.

Ocampo told US officials that the figure allegedly put away by Bashir was possibly nine billion dollars and "would change Sudanese public opinion from him being a 'crusader' to that of a thief."

The document was released by the whistleblowing website a day after its founder Julian Assange was released on bail in Britain over allegations of sex crimes in Sweden. It said Britain's Lloyds Banking Group "may be holding or knowledgeable of the whereabouts of his money".

Lloyds insisted it was not aware of any link with Bashir. "We have absolutely no evidence to suggest there is any connection between Lloyds Banking Group and Mr Bashir," a spokeswoman said.

In Khartoum, NCP official Rabie Abdul Atie called Moreno-Ocampo an "international liar" and said the allegations against Bashir were "ridiculous."

"I can confirm to you that there is no account of Bashir inside or outside Sudan."

The ICC’s first-ever warrant against a sitting head of state was issued against Bashir in March 2009 on charges of war crimes and crimes against humanity. The second was issued in July 2010 on charges of genocide.

Source: AFP