Several thousand civilians fled the Sudanese town of Abyei after renewed clashes in the disputed oil district where fighting this year raised fears of a return to civil war, officials said on Sunday.
"The general population, because of the sensitivity of the area and because of the experience of what happened in May, don't want to hear any shot of the bullet. It scares them," Abyei chief administrator Arop Moyak told AFP.
The region of Abyei, with its estimated half-billion dollar oil wealth, lies on the fault line between north and south Sudan with borders still unresolved more than three years after a peace agreement ended decades of civil war.
"Those who left is not less than 3,000, but there is a sign that some of them are coming back," Moyak said.
One person was killed and four to 10 others wounded when police and soldiers traded fire, less than two weeks after U.N. officials said that thousands of civilians were returning home after fighting flattened the town in May.
Police told Reuters the shooting started after a northern soldier in the joint military unit got into an argument with a trader in the town's market and police tried to intervene.
In May, scores were killed and more than 50,000 left homeless when northern and southern armies fought in the town, burning the settlement to the ground.
The origins of the May clashes are still unclear. Observers said it may have been sparked by a similarly small incident, reportedly a confrontation between northern and southern forces at a checkpoint.
Both sides pulled their troops out of the town after the clashes, and agreed to replace them with joint police and military units made up of northerners and southerners, as part of a road map peace agreement.
Moyak broke off urgent talks in the south Sudan capital Juba to return to Abyei on Saturday after the violence flared the previous day in a blow to hopes of a return to security after the devastating fighting of seven months ago.
"The assessment is ongoing, but right now we're looking at 400 to 500 households on the road towards Agok (from Abyei)," one aid worker told AFP.
"Most of the shops are closed and many of the traders are packing up. We don't have a sense of numbers, but the problem is the centre of town. On the periphery there are people who are still staying," the aid worker said.
In a dangerous development for stability in the disputed district, the clashes involved police and soldiers from joint units of former foes from north and south, whose deployment was supposed to restore security to the town.
Both north Sudan and the semi-autonomous south claim Abyei -- at stake is control over nearby oilfields and a key pipeline funneling crude to Sudan's Red Sea coast.
The boundaries of the town and surrounding territory were left undecided in the 2005 Comprehensive Peace Agreement that ended more than two decades of north-south civil war.
In June, rival politicians from north and south agreed to conduct joint patrols and share an interim administration in the town -- three years late.
Witnesses told AFP by telephone on Sunday that Abyei was calm and stressed that the fighting had not been as serious as in May. But aid officials said the renewed clashes posed a real setback to hopes that security would return.
The head of the U.N. mission in Sudan, Ashraf Qazi, deplored the clashes and appealed for calm to allow the peaceful implementation of the June agreement.
On Saturday, the local administrator said army troops would withdraw from the town, but it remained unclear when or whether this would happen.
Moyak has drawn up a budget of 287 million Sudanese pounds ($130 million) for 2009 but says he has not received a penny from the presidency.
"Up to now, we have not received anything from the president which is really making our movement towards peace-building difficult," he said.
In 2011, autonomous south Sudan is scheduled to vote on whether to break away as an independent state or remain united and share power with the north.
Abyei is to hold a separate vote on whether to retain its special administrative status in the north or become part of the south.
Besides its oil, Abyei is also the focus of a dispute over grazing rights between migratory Arab herders from the Messeria tribe, who are aligned largely with the north, and the Ngok Dinka, who are affiliated with the south.