Internal ethnic strife, a deep-rooted but often overlooked challenge facing newly independent South Sudan, has recently emerged as a threat to the country’s stability.

Last month, the South Sudanese army and United Nations reinforcements were sent to the town of Pibor in Jonglei state to prevent attacks by members of the Lou Nuer ethnic group against the Murle clan. In the past few months, over a thousand people have died and tens of thousands have been displaced in clashes that started last summer, as cattle raids prompted violence that quickly escalated.

Such internal instability has caught the Government of South Sudan (GoSS) flat-footed and highlights the desperate need for sustainable law enforcement and disarmament throughout the region.

While South Sudanese were united in the struggle for independence against Khartoum, tribal conflict throughout the region is not a new phenomenon. South Sudanese identify more with tribal affiliation than nationality. In a country of over 200 ethnic groups, this dynamic has produced divisions throughout society. Furthermore, when tribal affiliation overlaps with a reliance on a pastoral livelihood common to South Sudan, the potential for instability and violence grows.

The Lou Nuer tribe occupies the northern Akobo, Nyirol, and Wuror counties of Jonglei state. The Murle, a minority clan, occupies Pibor county. During the dry season, it is often necessary for the Lou to migrate south into Pibor as well as to the western part of the state to water and graze their cattle. This has repeatedly led to accusations of cattle theft. As a result, retaliatory attacks have erupted.

The volatile situation is exacerbated by Khartoum’s attempts to create instability. During the war, the regime of President Omar al-Bashir was known to have supported key actors in the south to combat the Sudanese People’s Liberation Army. Since the war ended in 2005, the GoSS has accused Khartoum of arming militias and civilians.

After decades of war, weapons—particularly small arms—are available throughout South Sudan, and too often even minor disputes are solved via the barrel of a gun. According to the International Crisis Group, attempts to disarm Jonglei’s population of 1.3 million have proved limited and uneven. In addition, the deepened divisions among localities have prompted politicians to incite violence against rival tribes.

As a sovereign state, the GoSS is under more pressure to address the country’s problems, whereas before July 2011, the primary objective of the GoSS was independence for the South Sudanese people. Juba has much at stake in making sure that this latest conflict is resolved. Already overwhelmed by its unresolved disputes with Khartoum, the failure of the new government in Juba to address the country’s internal challenges will not only reduce its legitimacy in the eyes of its people but provide opportunities for spoilers from the north and neighboring countries to incite instability.

The United States has a vested interest in making sure that the GoSS succeeds. In addition to its leadership in brokering the 2005 Comprehensive Peace Agreement, which outlined South Sudan’s path to independence, the U.S. has invested $10 billion in humanitarian aid. South Sudan’s plight has earned it significant support from the international community. However, some in the Obama Administration doubt the current government’s abilities to address the country’s challenges.

The Administration, which has so far failed to condemn the clashes in Jonglei, should urge President Salva Kiir to take steps to immediately end the violence and create sustainable plans for disarmament and law enforcement. Conflict prevention and resolution must remain a central focus for the policies of the Obama Administration and the international community as part of the commitment to building an independent and sustainable South Sudan.