United Nations (CNN) -- Ambassadors from Sudan and its newly independent neighbor, South Sudan, sparred at the U.N. Security Council Thursday as tensions rise between the two countries.
Despite the relatively peaceful secession of South Sudan earlier this year, unresolved issues between the two countries continue to simmer, and in some cases, boil. Decades of civil war between the north and south were ended with a U.S.-brokered peace treaty in 2005.
Ambassadors from the two nations appeared to talk past each other in the council chamber, making accusations of border incursions and violating peace treaties.
Sudan's U.N. Ambassador, Daffa-Alla Elhag Ali Osman, accused the south of supporting rebels in the restive regions of Southern Kordofan and Blue Nile, which are located in the north but largely swear allegiance to the south.
"We hope that the government of South Sudan would ... immediately halt its flagrant violations and aggressions and regain its sanity," said Sudan's U.N. ambassador, Daffa-Alla Elhag Ali Osman.
Last month, the United Nations said that Sudanese armed forces bombed refugee camp in South Kordofan. Osman claimed Thursday that the camp was used to train and support rebel fighters.
The U.N. confirmed Wednesday that 37 people were killed and 22 wounded in an attack in a border region of South Sudan. U.N. spokesperson Martin Nesirky said there was not yet enough information to say who was responsible for the attack.
The fate of the special administrative border region of Abyei continues to be tenuous.
The Security Council established a special peacekeeping mission to take control of the region from rival troops from the north and south in June. That mission's 853 peacekeepers currently deployed have been successful in restoring some peace and security, but South Sudan continues to insist that Sudan has failed to withdraw all its troops.
"It is not realistic or fair to expect South Sudan to do more than it has already done, without any movement from the Republic of Sudan," said David Buom Choat, South Sudan's acting U.N. ambassador.
Herve Ladsous, head of the U.N. peacekeeping department, told the Security Council Thursday that "very little progress" had been made in establishing a governing body for Abyei. Sudan and South Sudan continue to bicker over each other's nominees for that administrative body, Ladsous said.
Oil remains an extremely contentious issue between the two countries. Landlocked South Sudan is home to vast oil reserves, but most of the refining and shipping infrastructure is in Sudan, to the north. Ladsous told the council that the positions of the two countries remained "too far apart" to come to a long-term agreement.
Also in dispute is where exactly the border itself lies. Ladsous said that talks last month in Addis Ababa, Ethiopia "ended without agreement."
The UN has found and destroyed more than 100 unexploded ordinance and mines, Ladsous said. But so far only the South has assisted in that effort, and he appealed to Sudan to supply a team and maps to help find mines.
Ladsous warned the Security Council that the situation had the potential to become extremely volatile.
"A return to the negotiating table is absolutely essential to prevent a further descent of the two new countries into violence, which would inevitably have an impact on the whole region," Ladsous said.
South Sudan gained independence from Sudan on July 9 after a January referendum passed with 98.83% of the vote.