By Andrew Heavens
KHARTOUM (Reuters) - Heavy fighting erupted between Sudan'sarmy and southern Sudanese forces in the disputed oil-rich townof Abyei on Tuesday, aid workers said.
The fighting, which first erupted last week after a localdispute, is the latest of a series of clashes in the tensecentral Abyei region claimed by both Khartoum andsemi-autonomous South Sudan.
More than three years after a 2005 north-south peace dealto end decades of civil war, the sides have not agreed onborders or a government for the region.
Gunfire broke out at 4 a.m. local time (3 a.m. Britishtime), and clashes continued for at least four hours, saidhumanitarian staff, speaking on condition of anonymity.
"The fighting was heavy," said one aid worker. "It wasbetween SAF (Sudan's Armed Forces) and the SPLA (the southernSudan People's Liberation Army). We think it was acounter-attack by the SPLA.
"We are doing everything we can to calm the situation."
UN spokesman Kouider Zerouk confirmed fighting had brokenout again in the town, but said staff were still getting fulldetails of the attack.
The UN Mission in Sudan, which has evacuated many of itsstaff from the area, on Monday said it had started distributingfood supplies to up to 50,000 people who had fled the fighting.
The latest clashes came after failed attempts to reach aceasefire between north and southern troops. Commentators saidlast week's fighting was highly localised.
But the incident has underlined wider tensions over theregion. A report by US campaign group Enough in Januarydescribed Abyei as "Sudan's Kashmir" that could eventuallyspark another civil war if left unresolved.
(Editing by Matthew Tostevin)