Ayot Deng, who sells mobile-phone accessories from a stall in downtown Juba, the South Sudanese capital, laughed when asked whether war between North and South was imminent. "There will be no war," he said. "But if they [northerners] come at us, we shall not run away. We shall fight them right here, we are tired of being refugees and IDPs [internally displaced persons]."

Tension has risen between the Khartoum government and the Sudan People's Liberation Movement (SPLM). The tension, according to a Juba-based observer, has largely resulted from a lack of progress in the implementation of key provisions of the 2005 Comprehensive Peace Agreement (CPA).

The CPA, signed on 9 January 2005 in the Kenyan capital, Nairobi, ended a 21-year civil war between North and South Sudan, which affected millions of people and devastated southern states.

"The SPLM is frustrated because it believes the NCP [the ruling National Congress Party] is deliberately failing the CPA," the observer added. "The 11 October suspension of participation in the government of national unity was a loud and clear message of frustration."

The message was heard in international capitals, resulting in a White House meeting between US President George W Bush and Southern Sudan President Salva Kiir on 15 November.

"The SPLM and I have been agonising for long over the deliberate intention of the NCP to kill the CPA and dishonour our interim national constitution as a basis for our political partnership," Kiir told cheering supporters in Juba on 19 November.

"I visited the US and Kenya to mobilise President Bush, UN Secretary-General Ban Ki-moon and President [Mwai] Kibaki [of Kenya] for peace, not war," he added. "We have succeeded in rallying the international community to refocus on the CPA, Darfur peace process, Northern Uganda peace talks and development assistance to realise peace dividends for war-affected areas."

The government of the North, whose stance towards the SPLM has hardened, seized on the White House visit to hit back, raising the political temperature.

On 17 November, President Omar al-Bashir sharply criticised the SPLM and called for the re-opening of training camps for "the 'Mujahideen' [popular defence forces] militia to be ready for anything". The Mujahideen once fought the SPLM and have been cited in atrocities in the western Darfur region. Al-Bashir also said he would not budge "an inch" on the contested borders of the oil-rich Abyei region. "The NCP is ready for war and will not ... retreat from the 1905 border," he said.

The SPLM said the president's statement was a declaration of war, an assertion directly contradicted by the president himself.

“There will be no return to war as long as there is a glimmer of peace," Bashir told an NCP conference on 21 November, a gathering also attended by SPLM officials. “Dialogue is the only way to preserve national unity,” he added.

Sticking points

The SPLM gave a 9 January 2008 deadline for the resolution of several provisions in the CPA – including the Abyei protocol, redeployment of forces, demarcation of the border, population census, lack of transparency in oil sector management, democratic transformation and rule of law, and national reconciliation.

SPLM leaders deny there is a plan to break away from the rest of Sudan after the January deadline. "We want to win the election of 2009 as Sudanese and capture power in Khartoum through elections," Riek Machar, Vice-President of Southern Sudan, said.

"But we are concerned that more than two years after the CPA was signed, there are still political detentions … democratic transition is not taking place, censorship of the press is ongoing and the Abyei protocol has not been implemented," he added.

The oil-rich Abyei region, which was granted special administrative status by the CPA and given the option to decide in a referendum in 2011 whether to join the South, has proved a key sticking point.

A decision by the Abyei Boundary Commission was disputed by the NCP, leaving an administrative and political vacuum in a region with significant oil reserves. Machar said the SPLM had made four proposals over Abyei, but that the NCP had not responded.

"Obviously it is because of oil, because Abyei has oil," he told IRIN in Juba on 22 November. "They want to implement the protocol minus the areas that have oil because they want to carve them out of the South. This is not acceptable."

According to Machar, there was no transparency in the current oil operations and the Southern government "is not fully sure it is getting the correct revenues" from the resource.

"We also have the issues of the census [due in February 2008], the North-South border, which is overdue, and security arrangements," Machar said. "They were supposed to withdraw the SAF [Sudan Armed Forces] from Unity and Upper Nile States, leaving only the joint forces, but they still have 12,000 in Unity and 3,360 in Upper Nile. They should reduce the level of their troops to peacetime levels."

The census, according to analysts, is critical to providing benchmark data for power and wealth-sharing under the terms of the CPA. It is also a prerequisite for planning elections in 2009 and the planned 2011 referendum on the future status of the South.

Other SPLM leaders said they would demand a withdrawal of all southerners from the Khartoum government if there was no tangible progress on the implementation of the CPA provisions between 15 December and 1 January 2008.

"We will not wait until 2011," a senior SPLM leader told IRIN on condition of anonymity. He added that government troops were expected to withdraw from Abyei by 15 December - not by the end of year as suggested by Al-Bashir.

According to the Sudanese army, only 3,600 troops remain in the oil-rich region but SPLM sources say there are 17,000.

"From 15 December to 1 January will be crunch time," the official said. "At the moment, we are more or less two separate countries, so what will be difficult with breaking away? Even if they refuse to pay the oil money they owe us, we will survive; remember we fought for 20 years without a salary."

Returnees such as Deng, more concerned about settling down after years of displacement, however, say the government needs to put its house in order first.

"It was like returning home to new hardships," he said, claiming that years spent in the North had been just as hard as running his downtown stall. "We are patient with government, because it started from scratch. But how long can we wait for very basic services?"

War unlikely

Humanitarian workers in Southern Sudan are optimistic that the current standoff can be resolved. "We have a CPA that it is in the interest of all Sudanese and the international community to safeguard," said David Gressly, UN Deputy Resident and Humanitarian Coordinator for Southern Sudan.

"We are getting into the more difficult areas; it is going to be a bumpy road," he told IRIN. "But with support, the two parties will find a way forward. We [the international community] have to find a way to support the CPA process."

"The humanitarian situation in Southern Sudan has changed since the signing of the CPA," Gressly added. "A lot has happened from the UN point of view and also from the government point of view. We have seen real progress and resources are leaving the centre and starting to permeate downwards."

As a result, he added, the international community was now focusing more on recovery and development. He cited some US$57 million provided this year by the Southern Sudan government for infrastructure, 8,000km of roads surveyed and cleared of mines, 3,000 water points functioning, schools constructed and millions of textbooks procured.

Other aid workers, however, said the ongoing mobilisation of forces by both sides could threaten their work. "There is movement of troops, especially along the North-South border, which could affect access," said an international NGO worker.

A journalist in Juba pointed to another complication - a growing rapport between the SPLM and rebels from the war-ravaged Darfur region, who recently met in Juba to discuss a common strategy against the Khartoum government.

"A situation where Darfur rebels become cosy with the Southerners will stoke the tension," he said. "The NCP government will not encourage its perceived and real opponents to bunch together and it will get more messy if groups in the east also come into the picture."

Further tension, the Juba-based observer said, could lead to a skirmish, especially in Abyei, but full-scale war was unlikely at the moment.

"It takes one drunken soldier to shoot in the air; that would spark off some shooting from both sides," he said. "But neither the North nor the South can afford a war at this time."

This view was echoed by top SPLM leaders. "We believe there will be no war," Machar told IRIN. "If there is difficulty, we will call in IGAD [the Intergovernmental Authority on Development], the African Union, the UN Security Council, the international community."