Late Saturday evening, news trickled out from Sudan's most contested and militarized North-South border hotspot: the northern Sudanese army had invaded the town of Abyei with tanks.

The move, which followed two days of aerial bombardments and a declaration by President Omar al-Bashir that his government was dissolving Abyei's local government, is raising fresh concerns that Sudan could descend back into civil war before the South officially secedes on July 9.

According to southern leaders, the seizure of the strategic, oil-rich town was both a declaration of war by the northern government and a well-planned attempt to displace the Ngok Dinka people loyal to the south in order to permanently keep hold of Abyei after the south declares independence.

"The present occupation [by northern government forced] is illegal," said South Sudan's Information Minister Barnaba Marial Benjamin. "This is the responsibility of the [United Nations] Security Council to see that they are withdrawn."

Mounting clashes

The massive escalation in violence between Sudan's two armies in the historically volatile area came to head as a UN Security Council delegation arrived in the northern capital for a four-day visit.

Tensions began to spike on Thursday, when a rocket-propelled grenade round hit a UN vehicle that was escorting a convoy of northern troops.

By Saturday, a harsh northern response was well already underway in Abyei.

Southern army spokesman Colonel Philip Aguer said Saturday that at least 5,000 northern troops and allied proxy militias had swarmed Abyei from multiple directions, causing southern troops to scatter before the town fell to the northern army.



Concerns of civil war

Security analysts are now warning that the violence could spread quickly.

"After weeks of critical engagement from national and international actors to prevent escalation, the situation in Abyei has indeed boiled over, and the immediate priority is to contain the situation so as not to ignite broader conflict," said EJ Hogendoorn, Horn of Africa Project Director for the Brussels-based International Crisis Group.

Ambassador Princeton Lyman, President Obama's Special Envoy to Sudan, warned in a phone interview on Sunday that failure of the northern

Sudanese army to cease its offensive in Abyei, which he called a "disproportionate" response by the north to hostilities that flared Thursday, will result in setbacks in the process of normalizing US relations with the Sudanese government.

But one Western diplomat who spoke on condition of anonymity expressed skepticism of the ability of internationals to influence the northern government in the aftermath of the army's seizure of Abyei.

"We can issue statements, but where's the leverage?" the diplomat questioned.

Control of Abyei: A key sticking point

The fertile, oil-producing territory which both the north and south claim as proved to be the main sticking point between the two ruling parties since they signed the 2005 peace deal that ended decades of war.

International arbitration, multiple UN-backed treaties, and steady pressure from actors ranging from local civil society groups to Hollywood start George Clooney have failed to budge the North and South on their hardened positions on the future of the Abyei region.



Southern leaders on Sunday appealed to the international community, particularly the visiting UN Security Council delegation, to pressure the northern army to withdraw from Abyei, but northern leaders appeared unwilling to budge – perhaps emboldened by a clear military victory and the increasingly obvious fact that further clashes between northern and southern armies in Abyei would likely yield another decisive victory for the better-equipped northern army.