Arab tribesmen attacked a village in Sudan's highly charged Abyei border region, killing one civilian and injuring another, the territory's chief administrator said on Sunday.

Tensions are mounting in Abyei ahead of a referendum due in January 2011 on whether the territory should join south Sudan -- an oil-producing region that is preparing for a separate plebiscite on whether to split off as an independent country.

Abyei, which is close to key oil fields and includes rich pasture land, is used by two main groups, the Dinka Ngok, linked to south Sudan's Dinka people, and nomadic Misseriya Arabs, associated with the north

Some Misseriya leaders fear they would lose their grazing grounds if Abyei moved to the south -- even though the southern government has promised to let nomads cross borders.

"There was a Misseriya attack on the village of Maker, 12 miles (19 km) north of Abyei town on Saturday morning," Abyei chief administrator of Deng Arop Kuol said.

"They attacked it killing one civilian and wounding another man from the village ... We feel it is politically motivated to cause disruption."

Kuol said the attack on the Dinka Ngok village had come as a surprise as relations had been good in recent weeks.

A U.N. official confirmed the attack had taken place but said the identity and motivation of the attackers were unclear.

Both south Sudan's independence referendum and the Abyei vote were promised in the 2005 peace deal that ended more than two decades of north-south civil war.

Northern and southern soldiers clashed in Abyei town in May 2008 and analysts fear the territory could be a flashpoint of trouble after the votes.

Seven months ahead of the referendums, leaders from both sides have still not agreed on the position of their shared border, or named commissions to organise the voting.

Source: Reuters