Sudan's tangled conflicts fuel border battles
As Sudan and South Sudan slip ever close towards all out conflict, a related Sudanese civil war is intensifying - and, indeed, fuelling the international fighting.
Rebels in South Kordofan are taking advantage of the South Sudan-Sudan clashes in the oil fields in Heglig to fight their own battles nearby.
The state governor, Ahmad Haroun, who has been indicted by the International Criminal Court for alleged war crimes, says South Sudan is supporting the rebels.
Juba denies the accusations - but there can be no solution to the problems between Sudan and South Sudan without addressing the wars in South Kordofan and Blue Nile.
Mr Haroun points at the wreckage of a house, its tin roof a ruin scarcely held up by a battered brick framework: "The rebels have targeted the town, it's deliberate targeting," he says.Charred stubs of walls
Elsewhere in Talodi, a town in the Nuba mountains, there is evidence of shelling.
A jagged-edged hole larger than a football has been punched in a fuel tank at the power station.
A fire apparently burnt for three days, and the electricity was out for many more.
Some huts have been hit too, and all that remains is charred stubs of walls, the floor now open to the skies.
Mr Haroun and local residents told the BBC that Talodi was shelled by the SPLM-North rebels, as part of a failed assault on the town.
The government says development projects like roads and dams have been affected by the fighting.
Sudanese experts often say that the country's many wars were partly a result of the decades of neglect and underdevelopment of areas like South Kordofan.
End Quote Ahmad Haroun Governor of South Kordofan
These rockets and ammunition and supplies come from South Sudan”
What is apparent is how central this Sudanese civil war is to the ongoing problems between Sudan and South Sudan.
The SPLM-North fighters who took up arms against Khartoum in South Kordofan and in Blue Nile, which is situated in the east, once fought alongside the rebels who won independence for South Sudan.
They were left north of the border at separation.
A 2005 peace deal promised to sort out their situation within Sudan, but this never happened.
Now SPLM-North controls most of the Nuba mountains in South Kordofan, and can threaten towns like Talodi.
"These rockets and ammunition and supplies come from South Sudan," Mr Haroun says.
"The border is very near. They provide all the weapons. Until now the [rebel] soldiers are part of the South Sudanese army."
South Sudan says this is nonsense.Proxy armies
But a recent report by Small Arms Survey suggests there are strong links. It also accuses Sudan of supporting South Sudanese rebels.
The generals of the South Sudan Liberation Army (SSLA) are regularly seen in Khartoum, alongside other South Sudanese rebels.
Small Arms Survey has traced where the various rebel groups get their weapons from, and the evidence suggests, in essence, that both countries are running proxy armies in the other's national territories.
The timing of certain attacks raises eyebrows too.
When Sudan seized the disputed region of Abyei last year, the SSLA attacked just further south on the same day, tying up part of South Sudan's army.
The first South Sudan army advance on Heglig, at the end of March, coincided with a SPLM-North attempt to take Talodi.
"They orchestrated these attacks on Talodi and Heglig simultaneously, they did it from one plan and one target," Mr Haroun says.
Several sources say Darfuri rebels from the Justice and Equality Movement are also fighting in and around Heglig now.
Jem is one of several Darfuri groups that has signed an alliance with SPLM-North.
End Quote Hamid Tir
The prices are soaring because of the war... now people cannot afford to repair their bicycles so it has affected my income very much”
They are clearly taking advantage of South Sudan's occupation of the oil fields, a moment of real weakness for Khartoum, to launch further attacks in South Kordofan.
All this means that when delegations from Khartoum and Juba sit down to discuss security in Addis Ababa, proxy armies are high on the agenda.
For now, those talks are suspended.
But Sudan and South Sudan will not be able to make peace while rebel groups in both countries cloud the picture.
In the meantime, people are suffering.
The dominant narrative of the conflict in South Kordofan, at least in the Western media, has been that of Sudanese planes killing and injuring civilians in the Nuba mountains.
This undoubtedly happens.
The UN estimates hundreds of thousands more people, unable to farm due to the bombings, could flee the Nuba mountains - and hunger will begin to bite.
But people in the government-held areas have suffered too.
Mr Haroun says 35 people were killed, 54 wounded, and more than 28,000 were forced to flee the area because of the attack on Talodi.
It is impossible to independently verify these numbers, but a UN statement confirms many people did flee Talodi.
Hamid Tir said two of his brothers died in a car crash as they tried to escape the shelling.
He still has scars on his nose from the accident.
Talodi is now calmer, and people have started to return, but Mr Tir's bicycle repair business is struggling.
"The prices are soaring because of the war," he says.
"I used to get more before, but now people cannot afford to repair their bicycles so it has affected my income very much."War of religions?
Many of the people in Talodi South Kordofan have been given weapons to defend themselves.
Most are Arabs, who are often perceived to support the government.
"They are losing the war in Southern Kordofan, and they are dependent on trying to divide people along ethnic and religious lines," says Yassir Arman, the secretary general of the SPLM-North rebels.
The conflict in South Kordofan is far more complex than black African Nuba against Arabs, as it is sometimes portrayed.
Some Nuba, like Mr Tir, support the government.
The Nuba follow Islam, Christianity and traditional religions.
But Mr Haroun's followers do sometimes perceive this as a war of religions.
Ibrahim Mohamed Musa looks every day of his 55 years.
But he has an AK-47 strapped to his bike, and has signed up to a paramilitary police force.
"We are protecting our religion, so they will not take the area," Mr Musa says
"They are non-believers, and we are Muslim, so they will not defeat us."
Mr Haroun, who travelled around Talodi in a convoy of white 4x4s with only a small escort, was greeted by ululating women and men shouting "Allahu Akbar" (God is great) everywhere he went.
For these people he seems to be a hero. For many others he is anything but.
Mr Haroun was indicted by the ICC for his apparent role in alleged war crimes in Darfur, another Sudanese civil war.
He rejected claims his troops were committing abuses in South Kordofan.
"We have a professional army," he says.
What about the civilians dying from bombs rolled out of the back of the government's Antonov planes in the Nuba mountains?
"We try to do our best always to select military targets," Mr Haroun says.
"But as you know in a war you cannot measure things accurately. There is friendly fire sometimes."
SPLM-North says Mr Haroun is carrying out atrocities in the Nuba mountains and elsewhere in the region.
"War is becoming the only agenda of people within the regime headed by [President Omar al-] Bashir," Mr Arman told the BBC.
I asked Mr Haroun if he was worried he would face further charges from the ICC for alleged crimes in South Kordofan.
"I don't care about that, it is a political court, it is not professional," he says - and he accuses the SPLM-North - and the rebels' alleged South Sudanese backers - of carrying out human rights abuses.
As long as the war in South Kordofan continues, it is difficult to imagine a peaceful relationship between Sudan and South Sudan.
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. In Sudan, many of the residents of war-affected Darfur and the border states of Blue Nile and South Kordofan, depend on food aid. The UN said about 2.8m people in South Sudan would require food aid in 2013. The northern states tend to be wealthier, more urbanised and less reliant on agriculture.