By Khaled Abdel Aziz
KHARTOUM (Reuters) - Sudan said on Tuesday it had submitted an official complaint to the United Nations Security Council accusing South Sudan of causing instability in Southern Kordofan state, the latest sign of growing tension between the two nations.
Tensions have flared in the oil-producing state after South Sudan seceded last month, taking its oil fields with it. The Security Council said in July it was gravely concerned about violence in the volatile border territory.
U.N. officials say they are being granted only limited or no access to the area, which contains large populations that sided with South Sudan during the 20-year civil war.
"The complaint accuses South Sudan of causing instability, disrupting peace and offering support to rebel groups in the South Kordofan state," a spokesman from Sudan's Foreign Ministry told Reuters.
Earlier this month a U.N. report said the Sudanese army had carried out killings, arbitrary arrests, abductions, attacks on churches and aerial bombardment in Southern Kordofan that, if proven, might constitute war crimes and crimes against humanity.
In Washington, the U.S. State Department said it was deeply concerned by reports of continued aerial bombings of civilian areas in Southern Kordofan and called on both sides to agree to abide by a two-week ceasefire.
"We further call upon both sides to allow unfettered humanitarian access to affected populations in the state," State Department spokeswoman Victoria Nuland said.
The Sudanese Foreign Ministry statement accused South Sudan of providing military support to tribes in the area. It also said South Sudan violated the terms of the 2005 Comprehensive Peace Agreement (CPA) that ended decades of civil war.
Sudan's foreign minister, Ali Ahmed Karti, said in a copy of the complaint carried by the Sudanese news agency SUNA that Sudan was committed to stability and peace, but that the South Sudanese government was "hostile" toward its neighbor.
"The government of South Sudan has been standing behind all hostile activities in South Kordofan and has been supporting it with weaponry and equipment," Karti said.
Security Council diplomats in New York said they had not so far seen the complaint. But U.N. humanitarian chief Valerie Amos said the crisis in Southern Kordofan had "reached a critical point" with Khartoum having prevented aid agencies from replenishing stocks and deploying staff for six weeks.
"Unless there is an immediate stop to the fighting, and humanitarian organizations are granted immediate and unhindered independent access throughout South Kordofan, people in many parts of the state face potentially catastrophic levels of malnutrition and mortality," she said in a statement.
'HAND ON TRIGGER'
Rights activists have accused Khartoum of launching airstrikes and attacks in Southern Kordofan, targeting the state's ethnic Nuba group, in a bid to stamp out opposition and assert its authority after South Sudan's independence.
Sudan's government rejects the accusations, saying local groups launched a rebellion to try to control the territory.
"Despite the violations and abuses committed by the South Sudanese government and its constant incitement and support of rebel groups, the government announced a ceasefire," Karti said, referring to President Omar Hassan al-Bashir's unilateral announcement of a ceasefire last Tuesday.
Northern military spokesman Al-Sawarmi Khaled said in comments carried by SUNA Tuesday the situation was calm in Southern Kordofan at present.
"The ceasefire will remain an ethical commitment the armed forces took upon itself," Khaled said, adding that the military was closely monitoring the situation "with its hand on the trigger if there is any escalation."
After a week-long investigation in the Nuba Mountains, Human Rights Watch and Amnesty International said Sudanese army airstrikes had killed at least 26 civilians, wounded more than 45 and forced tens of thousands to flee.
The Sudanese government has dismissed the U.N. report as "unfounded" and "malicious" and has said it will form its own committee to assess the situation. Khartoum blames the violence on rebel groups.
"We were the first to acknowledge an independent South Sudan and extended a hand of cooperation," Karti said, accusing Salva Kiir, president of the new South Sudan, of claiming Southern Kordofan and the Blue Nile province, both north of the new border.
"The newly born state ... hosted rebel groups from Darfur, offering them camps, shelter, training and equipping them with arms to be used against the Sudanese republic," he said.
Karti called on rebel groups in Darfur and Southern Kordofan to "return to the voice of reason," accept the ceasefire and to sit down with Khartoum for talks.
(Writing by Dina Zayed in Cairo; additional reporting by Andy Quinn in Washington and Patrick Worsnip at the United Nations; editing by Matthew Jones and Anthony Boadle)