By Andrew Heavens
KHARTOUM (Reuters) - At least 23 people have died in clashes between tribespeople and Arab nomads near Sudan's north-south border, leaders in a contested region said on Monday, on the second day of a week-long referendum on southern independence.
Analysts cite the central region of Abyei as the most likely place for north-south tensions to erupt into violence during and after the vote, the climax of a troubled peace deal that ended decades of civil war.
U.S. President Barack Obama Saturday warned both northern and southern leaders not to use proxy forces over the voting period, highlighting international concerns that both sides might be resorting to tactics used in past campaigns.
Southerners are expected to vote to split from the mostly Muslim north, depriving Khartoum of most of its oil reserves.
In an offer that could be a major conciliatory gesture, former U.S. President Jimmy Carter told CNN that Bashir had proposed to take on all of the country's crippling debt if the south declared independence.
The gesture, if confirmed, would lift a huge fiscal burden from the south in the early days of its expected independence.
Leading members of Abyei's Dinka Ngok tribe, linked with the south, accused Khartoum of arming the area's Arab Misseriya militias in clashes Friday, Saturday and Sunday and said they were expecting more attacks in days to come.
In another sign of tension, southern army spokesman Philip Aguer said two men -- a Ugandan and a northern army soldier -- were arrested with four boxes holding 700 rounds of AK-47 ammunition in Juba Sunday night.
Aguer earlier said the north was also backing renegade fighters involved in recent clashes in the southern oil- producing Unity state.
The northern army's spokesman, al-Sawarmi Khaled, Monday denied any link to the ammunition or the clashes.
PEACEFUL VOTING
Observers said thousands of voters queued up for a second day of voting that continued peacefully across other areas of the south. The final results are expected by February 15, with preliminary results some two weeks earlier.
"Yesterday I tried my best but it was too much for me. Queues were too long. People were too emotional. Everyone wants to be first to decide his destiny," said Salah Mohamed, waiting outside a booth on the outskirts of the southern capital Juba.
"Today I could vote but still as you can see the crowds are still there ... I think the commission might need to extend the voting days."
A U.N. source, speaking on condition of anonymity, told Reuters there were reports Misseriya fighters were re-grouping in the settlement of Golih Langar Monday, 25 km (16 miles) north of Abyei town, the headquarters of U.N. peacekeepers in the region and international aid groups.
"A large number of Misseriya attacked Maker village yesterday (Sunday), backed by government militia ... The first day one person died, the second day nine, yesterday 13 ... It will continue. If not Maker then will attack every other village," said Charles Abyei, speaker of the Abyei administration.
Residents of the central Abyei region were promised their own referendum on whether to join the north or the south but leaders could not agree on how to run the poll and the vote did not take place, as planned on January 9.
Charles Abyei said the Misseriya attacked because they had heard false rumours the Dinka were about to unilaterally declare themselves part of the south.
Misseriya leader Mokhtar Babo Nimr told Reuters 13 of his men had died on Sunday's clash and accused southerners of starting the fighting.
"They attacked us because they don't want the Arabs to go south to water their herds but the cattle need water and they will go. If they continue to stop us going south this fighting will continue."
Southern army spokesman Philip Aguer said fighters captured after clashes with Galwak Gai's militia in Unity state on the eve of the vote said they had been sent from Khartoum.
"This is their last attempt to try to disrupt the voting process but they will not succeed," Aguer said.
(Additional reporting by Opheera McDoom and Jeremy Clarke in Juba; editing by Maria Golovnina)
