A bombing on the disputed north-south border of Sudan heightened concerns of renewed conflict in the region, but a Southern Sudan army official says the attack was aimed at rebels, not the south, and observers doubt this one incident would lead to anything more serious.

Sudan has been high on the U.S. foreign policy agenda, with top officials working to ensure a January referendum that could split Africa's biggest country into two is held on time. They are also working to avoid renewed conflict between north and south Sudan, who more than five years ago ended a decades-long war.

The borders of Northern Bahr Gazal and Southern Darfur, where the bombing occurred, are in dispute and the 2005 peace deal required the border between Southern Sudan and the north be demarcated. That exercise, however, has also been fraught with delays.

Col. Philip Aguer, spokesman for the Sudan People's Liberation Army, which protects oil-rich Southern Sudan, said Saturday that north Sudan's military bombed a disputed north-south border area but the attack was not meant for the south.

Both parts of Sudan are allowed to keep separate armies under a 2005 peace deal that ended their 21-year war.

Aguer said north Sudan military officers consulted with their southern counterparts through a joint military panel after the Friday bombing by an Antonov plane and determined the bombs were launched in the north, but landed in Southern Sudan territory close by. The panel, called the Joint Defense Board, is part of the 2005 peace deal and is meant to help avoid misunderstandings between the armies of the north and the south.

"The bomb fell in our territory by mistake and the SAF (Sudan Armed Forces) admitted it was not intentional," said Aguer. He said the bombing took place in Northern Bahr Gazal State, located in the southwest of the country and part of Southern Sudan, but would not give a precise location. Aguer said there were casualties but declined to give details.

The top U.N. official in Southern Sudan, David Gressly, said casualties are in the single digits and a U.N. team is going to the area to assess the situation

Lazaro Sumbeiywo, the Kenyan retired general who mediated the 2005 peace deal, said that since signing the agreement, north and south had only fought once, in 2008, in a dispute over the oil-rich area of Abyei.

Sumbeiywo declined to comment on the Friday incident but said when he went to assess the general situation in Southern Sudan two weeks ago, he did not find the semiautonomous region tense.

"In the sense that both parties need each other. The south has the oil and the north has the pipeline. How do you kill the conveyor and expect to get anything?" Sumbeiywo told The Associated Press.

The Obama administration, however, is worried conflict may be renewed because of the referendum on Southern Sudan's independence scheduled for January.

Officials have said the White House holds at least three meetings a week on Sudan in an effort to avoid a new outbreak of violence and President Barack Obama gets a daily briefings on the situation.

Last weekend, Sen. John Kerry, chairman of the Senate Foreign Relations Committee, met with Sudanese leaders and presented them with a proposal from the Obama administration to remove Sudan from the terrorist list. The proposal is in addition to one made in September offering a range of incentives, including possible restoration of full diplomatic relations between the U.S. and Sudan.

The U.S. offers follow conflicting statements from members of Sudanese President Omar al-Bashir's government that they may or may not recognize the referendum's results. It is widely expected that Southerners will vote in favor of separation come January.

Southerners fought a two-decade civil war against the Muslim, northern-dominated central government in which 2 million people died and more than a million headed north to escape the fighting. The independence referendum will be the culmination of the six-year transitional period that was part of the 2005 peace deal that ended that 20-year north-south conflict.

Aguer said that the north's military said they were targeting members of the Justice and Equality Movement rebel group, which has bases in Southern Darfur state bordering Northern Bahr Gazal. JEM is the most powerful of the Darfur rebel groups and has been fighting a rebellion in western Sudan's since 2003.

Several other rebel groups in the region have signed peace deals with the Sudanese government, but JEM remains one of the holdout groups.

On Thursday, the government's news agency reported that Sudan's intelligence chief called on Southern Sudan to arrest Darfur rebels hiding in the semiautonomous region. The agency also reported that National Security and Intelligence Service chief Lt. Gen. Mohammed Atta Almawla said some Darfur rebel leaders were in Northern Bahr Gazal state and two main towns in Southern Sudan. The report did not say which group the rebels belonged to.


Associated Press writer Tom Maliti in Nairobi, Kenya contributed to this report.