*Surge in violence threatens peace deal, southern stability
*Some locals say attack was revenge for cattle rustling
JUBA, Sudan, Sept 21 (Reuters) - More than 100 people were killed when tribesmen raided a south Sudan village, burning buildings and attacking churchgoers, officials said on Monday, in a further escalation of violence in the oil-producing region.
A surge of tribal killings this year has sparked fears for the stability of Sudan's underdeveloped south, still emerging from two decades of civil war.
Fighters from the Lou Nuer tribe attacked the village of Duk Padiet, home to a rival Dinka group, on Sunday morning while many of the villagers were in church, officials told Reuters.
The extent of the carnage only emerged on Monday when officials reached the remote settlement in Jonglei state.
A total of 51 villagers and 28 southern soldiers, national security and police officers guarding the settlement were killed, said southern army spokesman Kuol Diem Kuol.
"From the attackers 23 bodies were found on the ground. These attackers were found in uniform with arms and organized in a military organisation in platoons with G3 rifles," he said.
The United Nations estimates more than 1,200 people have died in ethnic attacks in south Sudan this year.
Some of the fiercest fighting has been in Jonglei, parts of which are included in a largely unexplored oil concession operated by France's Total.
Southern politicians have accused their former civil war foes from north Sudan of arming rival tribes to destabilise the region in the build-up to elections in 2010 and a referendum on southern secession in 2011. Khartoum denies the accusation.
THOUSANDS FLED AS BUILDINGS BURNED
"This is a campaign against the Comprehensive Peace Agreement (the faltering 2005 accord that ended Sudan's north-south civil war) and against the people of Duk," Mayen Ngor, the commissioner of surrounding Duk County, told Reuters by phone from near the scene of the attack.
Ngor said the attackers burned down 260 huts, the police station and local government buildings, injuring 46 people and forcing thousands to flee.
Around two million people died in the 1983-2005 war between Sudan's Muslim north and mostly Christian south. The conflict also set southern tribes against each other as the north backed rival southern militias.
Some analysts and southern leaders say they fear the new violence marks a return of the southern militias, backed by groups trying to undermine the peace deal, or local leaders, strengthening their power bases in the run-up to elections.
The 2005 peace deal which promised elections and a referendum also gave the south a share of the country's oil wealth and set up a semi-autonomous southern government.
North-south relations have remained tense and analysts say many of the northern political elite are nervous about the referendum, and the prospects of losing the south, the source of most of Sudan's proven oil reserves.
South Sudan has long been plagued by ethnic clashes, mostly fought over cattle and related feuds. But observers have been shocked by the scale of this year's violence, where tribal fighters have attacked villages and killed women and children.
Members of the Lou Nuer tribe this month denied their fighters had joined militias, telling Reuters most of the recent raids were revenge attacks for past cattle rustling.
"It is just cattle raiding ... It's just revenge," said William Khor Reath, executive director for Akobo County, a mostly Lou Nuer area in Jonglei state.
Traditional disputes have been exacerbated by a ready supply of guns left over from the civil war. (Editing by Andrew Heavens and Tim Pearce)
Jonglei state in Sudan. 
The army of southern Sudan says more than 100 people were killed when a local tribe attacked a rival group in the southern state of .

Gunmen from the  tribe attacked a village of the  tribe on Sunday, driving away security forces who were guarding the remote settlement of Duk Padiet.  army spokesman Kuol Diem Kuol said Monday that the dead include 23 attackers, 28 security forces, and more than 50 villagers, with 46 more injured.

"From the attackers 23 bodies were found on the ground. These attackers were found in uniform with arms and organized in a military organisation in platoons with ," Kuol said.

Jonglei state has experienced multiple deadly clashes involving the Lou Nuer, the Dinka Hol, and other tribes this year.

The area has long been the scene of violent cattle raids between the groups. Southern Sudanese officials say northern Sudan's ruling party is organizing the attacks to spark conflict and undermine the 2005  that ended Sudan's civil war, which calls for the semi-autonomous south to vote on full independence in 2011.

The  has repeatedly denied the accusations.