17 May 2012 Last updated at 22:40 ET

Mbeki arrives in Sudan for crisis talks

South Sudan's army took control of the disputed Heglig oilfield in April

Former South African President Thabo Mbeki has arrived in Khartoum to attempt to restart negotiations between Sudan and South Sudan.

The African Union's mediator is due to meet Sudan's President Omar al-Bashir to try to set out an agenda and timetable for talks.

Heavy fighting between Sudan and the new nation of South Sudan brought them to the verge of war last month.

The UN has threatened sanctions if the situation is not resolved swiftly.

According to a United Nations Security Council resolution, talks aimed at resolving the dispute should have started this week.

South Sudan - which only seceded from its northern neighbour last year - said it is prepared to talk without preconditions, while Sudan has said it wants negotiations to focus on security.

Territorial dispute

The latest crisis began in April when South Sudanese troops took over the Heglig oilfield, which is one of Sudan's biggest sources of revenue.

South Sudan claims the oilfield falls within its territory, but the exact location of the border still had not been decided when the South became an independent nation last July, taking most of the united country's oil with it.

Under international pressure, South Sudan later withdrew from Heglig.

Main disputes between the two Sudans

• The amount the South should pay Sudan to use its oil pipelines
• Demarcating the border
• Both sides claim Abyei
• The rights of each other's citizens now in a foreign country - there are estimated to be 500,000 southerners in Sudan and 80,000 Sudanese in the South
• Each accuses the other of supporting rebel groups on its territory

• South Sudan refugees flown home

At a meeting of the Security Council on Thursday, members adopted a resolution demanding the finalisation of a jointly-run administration and police force for the disputed border region of Abyei near Heglig.

The United Nations has said that unless the border question and other issues are resolved within the next three months, it will consider imposing sanctions.

For that, the two countries need to sit round the negotiating table, but the latest round of fighting has derailed talks.

The two countries are also still to agree on what rights their citizens should have in the other - some 500,000 Southerners are now foreigners in Sudan, along with some 80,000 northerners in the South.

A deadline for a group of some 15,000 Southerners to leave Sudan expires on Sunday - the first group has already started flying to the South, a country some of them had never visited before.

In addition to meeting President Bashir and other senior officials in Khartoum, Mr Mbeki is expected to travel to the South's capital Juba to try to get the two sides to agree to new talks.

Sudan: A country divided

• Oil fields
• Geography
• Ethnic groups
• Infant mortality
• Water & sanitation
• Education
• Food insecurity

Show regions

Both Sudan and the South are reliant on their oil revenues, which account for 98% of South Sudan's budget. But the two countries cannot agree how to divide the oil wealth of the former united state. Some 75% of the oil lies in the South but all the pipelines run north. It is feared that disputes over oil could lead the two neighbours to return to war.

Although they were united for many years, the two Sudans were always very different. The great divide is visible even from space, as this Nasa satellite image shows. The northern states are a blanket of desert, broken only by the fertile Nile corridor. South Sudan is covered by green swathes of grassland, swamps and tropical forest.

Sudan's arid north is mainly home to Arabic-speaking Muslims. But in South Sudan there is no dominant culture. The Dinkas and the Nuers are the largest of more than 200 ethnic groups, each with its own languages and traditional beliefs, alongside Christianity and Islam.

The health inequalities in Sudan are illustrated by infant mortality rates. In South Sudan, one in 10 children die before their first birthday. Whereas in the more developed northern states, such as Gezira and White Nile, half of those children would be expected to survive.

The gulf in water resources between north and south is stark. In Khartoum, River Nile, and Gezira states, two-thirds of people have access to piped drinking water and pit latrines. In the south, boreholes and unprotected wells are the main drinking sources. More than 80% of southerners have no toilet facilities whatsoever.

Throughout the two Sudans, access to primary school education is strongly linked to household earnings. In the poorest parts of the south, less than 1% of children finish primary school. Whereas in the wealthier north, up to 50% of children complete primary level education.

Conflict and poverty are the main causes of food insecurity in both countries. The residents of war-affected Darfur and South Sudan are still greatly dependent on food aid. Far more than in northern states, which tend to be wealthier, more urbanised and less reliant on agriculture.