Southern Sudanese officials on Thursday blamed the north's military for attacks that killed more than 100 people this week around a disputed town between north and south Sudan.
Women and children fled en masse from the town of Abyei, a region that has long been seen as the major sticking point between north and south. Southern Sudan voted in January to secede from the north and is on course to become the world's newest country in July.
"Now all the women and children have evacuated the town. They have moved south because they expect more fighting in the town," said Father Peter Suleiman, a Catholic priest who spoke to the Associated Press by phone from Abyei town on Thursday.
Col. Philip Aguer, the spokesman for Southern Sudan's military, said more than 70 people were killed in fighting between Sunday and Tuesday. Aguer said that armed members of the Arab cattle-herding Misseriya tribe, militia fighters and northern army forces attacked several villages north of the town of Abyei.
Aguer said the southern government blames the north's Sudanese Armed Forces and the government of Sudanese President Omar al-Bashir for the violence.
"The attackers have occupied many villages north of Abyei and maybe their intent is to move southward so this is why people are fleeing," Aguer said.
Fighting continued Wednesday in the village of Maker Abyior, 10 miles (15 kilometers) north of Abyei town.
Aguer said he did not know the death toll from that fighting, but an international official in Abyei told The Associated Press of witnessing 33 bodies buried in a mass grave late Wednesday.
Most of the dead were wearing police uniforms, said the official, who spoke on condition of anonymity because of the sensitivity of the matter.
The top government official in Abyei, Deng Arop Kuol, also said the attackers are members of the Sudan Armed Forces, the northern military. He said the forces used heavy machine guns, and that Abyei's police force have only rifles.
Still, Kuol says his people will continue to fight back against attacks.
"People will still fight back. Even if you have a stick and the other has gunfire. You will have to fight back," he said.
The southern claims of northern military involvement in this week's attacks have not been independently verified. Al-Bashir's government has denied such accusations in the past.
Abyei had been promised a separate self-determination vote, but its future is now being negotiated by officials from the north and south. If the intensely disputed issues surrounding this fertile oil-producing region are not resolved soon, further violence is likely.
"The people of Abyei have long fought for a right to determine their future," said Clare McEvoy of the Geneva-based Small Arms Survey, a research group that studies the conflict in Sudan. "Denying them this right is very shortsighted and is likely to lead to continued conflict in the area."
McEvoy says the conflict in Abyei "could easily spread and is in danger of seriously compromising relations" between the north and south.
The head of the U.N. mission issued a statement on Wednesday saying that this week's violence in Abyei is a "clear violation" of the agreement signed by northern and southern leaders in January that pledged both sides to work to improve security in the tense region.
U.S. State Department spokesman P.J. Crowley called for calm in a Thursday statement.
"The United States condemns this week's violent clashes in the Abyei region and urges all parties to refrain from taking actions or making statements that could further heighten tensions there," the statement read. "The United States calls on local and national authorities to ensure that the U.N. Mission in Sudan has the access required to protect civilians, increase patrols where fighting is taking place, and engage with local leaders to restore calm."
The latest violence comes as leaders of Sudan's north and south are meeting in Ethiopia to discuss issues like border demarcation and wealth sharing after the oil-rich south declares independence in July.
The meeting is the first high-level round of negotiations between north and south since Southern Sudan's independence referendum in January. The talks will be a key indication of the political dynamics between the two sides at a time when many questions have yet to be answered about relations between north and south after southern independence.
The future of Abyei, which both the northern and southern governments stake claims to, is widely considered to be the one issue that could prevent the peaceful breakup of Africa's largest country.
According to the terms of the 2005 north-south peace deal, the agreement that ended more than two decades of civil war, the northern and southern armies are not to deploy around Abyei.
The ability of the Misseriya to graze their cattle through the fertile Abyei region and to the River Kiir is in question due to the ongoing violence, which the pro-southern Ngok Dinka people of Abyei accuse the Misseriya and the northern government of starting.