South Sudan on Tuesday accused its northern neighbor Sudan of bombing a border town, violating a non-aggression agreement between the two nations just hours after it was signed.
South Sudanese military officials said Sudan launched an attack early Saturday on the disputed town of Jau. Military spokesman Col. Philip Aguer said the area was shelled by Sudanese Armed Forces in the early morning then bombed by the Sudanese Air Force during the day.
Four South Sudanese soldiers were wounded in the attack, said Aguer.
A military spokesman in Sudan could not be reached for comment late Tuesday.
Jau lies on the border of South Sudan's Unity State and Sudan's South Kordofan state and has been claimed by both countries. Sudan is currently battling the SPLM-North, a rebel group that was linked to South Sudan's Southern People's Liberation Movement before the country gained independence in July. Khartoum has repeatedly accused South Sudan of continuing to support the SPLM-N, claims that Juba denies.
News of the attack comes on the heels of a memorandum of understanding on non-aggression signed by both governments in Ethiopia Friday evening.
South Sudan's Deputy Defense Minister Majak Agot Atem told reporters Tuesday that the agreement was based on a number of principles including "respect of each other's sovereignty and territorial integrity" and the "rejection of the use of force in conducting their relations."
The agreement was signed during talks in the Ethiopian capital to resolve outstanding provisions of the 2005 Comprehensive Peace Agreement, which ended more than two decades of civil war between the two sides.
At the center of the talks is the division of the two nations' once-unified oil industry. As part of the peace agreement, South Sudan declared independence from Khartoum, inheriting nearly three quarters of Sudan's oil production in the process. All of South Sudan's oil must still exported through pipelines through Sudan, but the two countries cannot agree on the transport fees Juba should pay.
In lieu of an agreement, Sudan recently declared it would take a percentage of South Sudan's oil as in-kind payments. South Sudan in turn accused Khartoum of stealing nearly all of its oil and decided to shut down all production in its oil fields, depriving Khartoum of a critical source of income.
The two countries are also far apart on other issues such as the demarcation of the north-south border and the status of the disputed Abyei region.
"Since the confiscation of South Sudan's oil, relations (between the two countries) are still teetering on the brink," said Atem.
While a cause of constant tension, many observers saw the oil industry as a kind of glue holding the two countries together. With the flow of oil now shuttered, many worry about a return to open warfare.
Aguer said Tuesday that Sudanese Armed Forces are massing along the border with South Sudan. Aguer said Sudan had positioned four battalions around Jau and three others along the border of Sudan's South Darfur state.
"Khartoum has never recognized the border between South Sudan and Sudan and they are now expanding their territory," he said.
"All these are indicative of escalation," said Atem. But Atem said the two countries could still back down from the brink by adhering to the non-agression agreement signed in Ethiopia. "This (agreement) if the two parties commit themselves to implementing each and every clause of it, will definitely have a considerable bearing on improving the mutual relations between the two countries."
Meanwhile, a half-million South Sudanese people living in Sudan will have the choice to go home after a new deal was struck between the two countries, but a fast-approaching deadline leaves little time to make the difficult journey, an international migrant agency said.
The agreement sets an April 8 deadline for South Sudanese to choose to return home or to risk staying on in Sudan, where they will be required to "regularize" their status _ an unclear requirement that does not necessarily mean they will gain citizenship with equal standing, the International Organization for Migration said.
Already, some 120,000 South Sudanese have registered with the U.N. refugee agency seeking to depart Sudan.
Jumbe Omari Jumbe, a spokesman for the Geneva-based organization of 146 nations, said the April deadline leaves too little time for half a million people to travel in such a vast country without adequate roads or other transportation.
IOM had hoped that the nations might pick a more distant deadline in their agreement Sunday, he said.
There are already more than 11,000 South Sudanese stranded at Kosti, a city along the White Nile River south of Sudan's capital Khartoum, where they are waiting to be transported to the South.
"It is logistically impossible to move half a million people in less than two months, in a vast country like Sudan with many infrastructural challenges. We desperately need enough time to guarantee safe and dignified return of these people" said Mohammed Abdiker, IOM's director of operations and emergencies.
IOM said the agreement between the two nations specifies how security should be handled for people returning along the road and at borders, and even limits how much baggage they can carry.
The organization said it already has helped 23,000 South Sudanese return home from Khartoum and other Sudanese cities, using dozens of river barges along with trains, trucks and chartered aircraft.
But Khartoum, citing security concerns, has refused to allow humanitarian aid agencies into the region. A deepening food crisis also has been spurred by erratic rains in Sudan and instability due to the violence.
John Heilprin contributed to this report from Geneva.