Political and military instability grows with every passing day in the world's youngest country, South Sudan. Clashes between two army factions that began last week has triggered a wave of violence that is causing hundreds of deaths. The country got its independence from Sudan two and a half years ago, and shows some of the worst rates of poverty, health and education in the world, despite its millionaire oil exports. In an area of about 620,000 square kilometers, between 8 and 10 million people belonging to more than sixty ethnic groups live.

Who is facing whom?

Informations stemming from South Sudan point to a division within the South Sudan army between supporters of current President Salva Kiir Mayardit (left image) and those of his former Vice President Riek Machar (right image). Both Kiir and Machar hail from the Sudan People's Liberation Movement (SPLM), the political and military organization that led the war of independence against Sudan. Together, both leaders had ruled the country since 2005, when South Sudan was granted autonomy within Sudan, until July of this year when Kiir dismissed Machar from his post as South Sudan Vice President.

Why are they struggling?

Both leaders vie for the SPLM presidency, which is now controlled by Kiir himself. Control over SPLM de facto amounts to control over South Sudan presidency. At first, Machar denied being involved in violence or leading opposition forces to Kiir, but yesterday he admitted to the BBC that the rebels are actually under his control. For months Machar has accused President Kiir of driving South Sudan towards dictatorship and tribalism and of doing nothing to reduce corruption within the government. Now, the former Vice President is also demanding that the army overthrow Kiir.

Meanwhile, Kiir had long said that Machar was preparing a coup against him. Those opposed to Machar recall that he is also a controversial leader: he is accused of leading a massacre that killed 2,000 people in the city of Bor in 1991. Six years later, he also reached an agreement with Sudan to abandon the independence rebellion; immediately he became advisor of Sudanese President Omar al-Bashir. But in 2000 he again changed sides and retook arms against Khartoum.

Is it an ethnic struggle?

International media suggest that, in fact, present violence was sparked by a fighting that began on December 15th between Dinka and Nuer members of the presidential guard. The Dinka and the Nuer are the two main ethnic groups of South Sudan. Kiir is a Dinka and Machar, a Nuer. It is difficult to determine the links between all these facts in terms of causes and consequences, but informations collected by several human rights organizations in South Sudan conclud that violence has now an ethnic dimension. Amnesty, for instance, says there was "mounting evidence that troops and armed civilians" from the Dinka and Nuer communities are killing civilians " based on their ethnic background".

Several experts argue in this article that there is certainly an ethnic issue that is being used by the two main contenders. But the experts also keep in mind that some Dinka support Machar and some Nuer are backing Kiir. Similarly, the Shilluk -another ethnic group in South Sudan- are divided between the two leaders.

Which are the consequences on the ground?

The fighting has left at least 500 dead so far. In addition, the United Nations yesterday reported that the fighting had displaced 62,000 people, including 20,000 in South Sudan capital city Juba. Machar says that most of the country is now in the hands of his rebels, including the region of Unity, which concentrates most of the oil production. The South Sudanese army yesterday admitted that it had lost control of Unity capital Bentiu. The army had previously acknowledged that Bor (Jonglei region) was also escaping from its hands.

Destabilization generated by the confrontation has also enabled the advance of a Nuer rebel group, the Movement for the Liberation of Southern Sudan (SSLA), which is led by a former army commander, Peter Gadet. SSLA is strong in the Bor region. A BBC profile underlines that Gadet is now a Machar ally, with the common goal of overthrowing Kiir.

Is there any involvement from other countries in the region?

As usual in such situations, the African Union has called for an immediate cessation of hostilities, or at least a "humanitarian truce" for Christmas. The organization is mediating to avoid a further escalation. The negotiating team includes ministers from Kenya, Uganda, Djibouti and Somalia.

Some media have said that Uganda is directly involved in the conflict, supporting President Kiir. The Ugandan Government has denied that, and the website of the Ugandan Foreign Ministry says that Ugandan troops are in Juba "on the invitation of the Government of South Sudan" in order to evacuate Ugandan citizens living in South Sudan.