April 21, 2011: Sudanese troops have pushed South Sudanese forces out of Heglig, a border area containing most of Sudan's remaining oil production. The two countries are now at war and Sudan says the conquest (or "liberation") of Heglig was just the beginning.

The Sudan-South Sudan War is a war over old maps. South Sudan bases its claim to the disputed Heglig oil field and its immediate environs upon a boundary map drawn in 1956 wich places the Heglig area in Unity state, which is now part of South Sudan. Sudan argues that the map is not definitive and that the 2005 Comprehensive Peace Agreement (CPA) specified that there would be a new demarcation process and decision. The CPA ended the 22 year-long war (1983-2005) between the north and the south. Sudan, however, has dragged out demarcation discussions.

Initially the north was trying to thwart the south’s drive for independence, an option that was included in the CPA. The south, however, opted for independence, which gave the south control of about 75 percent of pre-division Sudan oil production (which at the time of division in July 2011 was around 430,000 barrels per day). Since independence, the north has been trying to recoup oil revenue by asserting control over pipelines and oil transport (the major pipeline runs through northern territory to Port Sudan). The north has also tried to gain physical control over other oil producing areas. In the case of Abyei, the north launched an invasion of the area that basically drove away a substantial number of southern supporters. Control of Abyei was supposed to be decided by plebiscite. With its attack on Heglig the south demonstrated that it can return the favor. Heglig is now Sudan’s largest oil field, producing 55,000 to 60,000 barrels of oil per day.

South Sudan wants international arbitrators to decide on the status of Heglig. South Sudan said that its troops were withdrawing from Heglig and the withdrawal would soon be complete. Israel has been asked to contribute forces to a reinforced peacekeeping mission in South Sudan. In the past Israel has provided aid to Kenya. Israel may have provided some covert support to south Sudanese rebels during the Sudan Civil War.

April 20, 2012: Sudan claimed that its military had re-taken the Heglig oil field from South Sudan. Large crowds gathered in Khartoum to celebrate the alleged victory. In South Sudan the government said that it had ordered its forces to withdraw. The implication was that international pressure to end the fighting had influenced the south’s decision. The UN called the south’s attack on Heglig an illegal act. The southern government, however, insisted its claim to the oil field remains valid and the decision to withdraw did not affect that claim.

Uganda indicated today that it might intervene militarily in the new Sudan-South Sudan War on behalf of South Sudan if Sudan invades southern territory. During the civil war Uganda provided southern rebels in the Sudan Peoples Liberation Army (SPLA) with arms, ammunition, medical aid, and food. Uganda contends that the Lords Resistance Army (LRA) was created by Sudanese intelligence (north Sudan) to fight a proxy war against Uganda.

Rebels belonging to the Sudan Peoples Liberation Movement-North (SPLM-N) claimed they killed 79 Sudanese troops in two battles in Blue Nile state (Sudan). The battles took place on April 17 and 18. One battle occurred 30 kilometers south of the state capital, Ed Damazin.

The Central African Republic (CAR) claimed that Sudanese rebel forces killed 11 CAR soldiers in an ambush near Amdafok, which is located near the CAR-Sudan border (across from the Darfur region in western Sudan).

April 19, 2012: The Darfur rebel group, the Justice and Equality Movement (JEM) claimed that its fighters fought with a Sudanese Army unit near Kharasana (South Kordofan state, near Heglig). The JEM is now officially an ally of the SPLM-N. The JEM and SPLM-N belong to the Sudan Revolutionary Front (SRF) resistance organization.

The UN declared South Sudan’s occupation of the Heglig oil field to be illegal.

April 18, 2012: A firefight between Sudanese and South Sudanese forces left 22 soldiers dead. The battle occurred near the town of Meiram, on the border between Sudan (South Kordofan state) and South Sudan (North Bahr el Ghazal state).

April 17, 2012: The Sudanese Air Force reportedly attacked a military position occupied by UN peacekeepers in South Sudan. The UN peacekeepers were serving with the UN Mission in South Sudan (UNMISS). The attack did not cause any casualties.

The government of South Sudan reported that a significant number of Murle tribal fighters are refusing to turn in their military weapons. South Sudan is attempting to disarm tribal militias in Jonglei state.

Japan’s Toyota Corporation announced that it has developed a plan to build an oil pipeline from South Sudan to Kenya’s seaport of Lamu. The pipeline is part of the Lamu Port-Southern Sudan-Ethiopia Transport Corridor (Lapsset) project.

April 16, 2012: The Sudanese Army (Sudan Armed Forces, SAF) attacked several police and military observer position near posts Kuek in South Sudan (Upper Nile state). South Sudan claimed that the Sudan Peoples Liberation Army (SPLA, the south’s military forces) would counter-attack.

April 15, 2012: Sudan’s SAF and South Sudan’s SPLA reported armed clashes along the border of Sudan’s South Kordofan State and South Sudan’s Upper Nile state.

Five days after seizing the town of Heglig, South Sudanese forces still remain north of the border. This has amazed many military analysts since the north has a huge edge in combat power.

South Sudan’s SPLA has around 140,000 soldiers. It is basically a guerrilla force armed with light infantry weapons. It does have between 150 and 200 tanks (mostly Cold War-era Russian T-55s but some more modern T-72s). How many are operational is unknown. The SPLA has 60 to 70 artillery pieces. Its air force consists of a few transport helicopters and one light transport plane (prop-driven).

Sudan has an army (SAF) of around 100,000 troops but its ground forces are much stronger than those of the south. Sudan has around 400 medium tanks, including 60 Chinese-made Type 59 tanks. 300 of its tanks are T-54s or T-55s. It also has around 100 light tanks and 400 armored personnel carriers. Its armor is operational. The SAF has around 800 artillery pieces (tube artillery) and 600 multiple rocket launchers. The tanks, APCs, and artillery give the SAF a huge edge in fighting the SPLA. Then comes the air force, another huge northern advantage. Sudan’s air force has 61 jet combat aircraft (25 of them Mig-29s) and 23 transports. Several of the transports (Antonovs) are rigged as bombers (ie, pushing the bombs out the transport’s doors). Sudan also has between 35 and 30 attack helicopters. Its attack helicopter pilots have had a lot of experience flying missions against rebels in Darfur.

Three wild cards, however, could add muscle to the south. Uganda now has eight Russian Sukhoi Su-30 jet fighters, which could provide South Sudan with some air cover. Uganda also has a well-trained army, by east African standards. Kenya’s best ground forces are engaged in Somalia but Kenya could also provide South Sudan with some ground forces and air power. The biggest wild card is Ethiopia, which has a powerful military and capable air force. Ethiopia has indicated that it would prefer to remain neutral (Ethiopia has a peacekeeping force in Abyei). However, Ethiopia is also working with Kenya on building a pipeline to carry South Sudanese crude to Kenya’s seaport of Lamu. The stage is set for a wider war in east Africa if the Sudan-South Sudan War continues. The war would also involve numerous rebel groups and militant tribal militias operating throughout Sudan and South Sudan.

Then there are the ethnicity and religion factors. Sudan considers itself Arab and Moslem. Sudan actually considers itself an Islamic republic (religious dictatorship). South Sudan, Ethiopia, Kenya, and Uganda are all largely Christian and black African. The animosity between black Africans and Arabs is thousands of years old and still active. It means that the Arab world will hold their nose and support Sudan in their war against the "blacks". Sub-Saharan (black) Africa will support South Sudan. It's an old war and it's not just about Sudan.

April 14, 2012: Sudan Air Force Antonov transports dropped bombs on the town of Bentiu in South Sudan (Unity state). Five people were reportedly killed in the attack.

April 13, 2012: Sudan claimed that its military forces had launched a counter-attack on South Sudanese troops holding the Heglig oil field and the town of Heglig (South Kordofan state). South Sudan claimed that there were no counter-attacks. Sudan said that it would use all legitimate means to regain control of Heglig.

April 10, 2012: Sudan accused South Sudan of launching a cross-border attack into Sudan’s South Kordofan state. Sudan claimed that the south had seized the town of Heglig and Heglig oil field. South Sudan claimed that it was acting to protect itself from repeated attacks by the north launched from the Heglig area. The south also accused the north of launching air attacks on southern territory. South Sudan acknowledged that it had taken Heglig and repulsed a Sudanese counter-attack.

South Sudan accused Sudan of bombing the village of Abiemnom (40 kilomters south of the Sudan-South Sudan border) in Unity state.

April 9, 2012: South Sudan reported that a former SPLA general had defected to the north. This is the second time that former general David Yauyau has switched sides. Yauyau is member of the Murle tribe. The Murle have accused the government of South Sudan of favoring the Lou Nuer tribe. The Murle and Lou Nuer have had several major armed confrontations in the last year.

April 8, 2012: The Abyei Joint Oversight Committee (AJOC) reported that it is investigating the plight of the 110,000 people displaced by Sudan’s May 2011 attack on the region.

April 5, 2012: Police in Khartoum fired tear gas and warning shots at a funeral procession which the police claimed was turning into an anti-government protest. Around 4,000 people participated in the procession. The funeral was for a student political activist who witnesses claim was killed by Sudanese security agents on April 2.

April 4, 2012: South Sudan claimed that it had shot down a Sudan Air Force jet aircraft which was conducting a bombing raid on South Sudanese territory. Sudan denied that it had lost an aircraft and that it was conducting bombing raids on the south.

April 3, 2012: South Sudan continues to accuse China of favoring the north in the continuing political and economic struggle over oil transport costs. Sudan’s Greater Nile oil pipeline is operated by the Greater Nile Petroleum Operating Company. China’s China National Petroleum Corporation owns 40 percent of the Sudanese pipeline company. The pipeline is some 1,600 kilometers in length. It runs from South Sudan’s Unity state north through Sudan’s South Kordofan state and from there to the Red Sea port of Port Sudan.