Khartoum – Clashes erupted in Abyei between north and south Sudanese troops, the southern army said, just days after a deal to demilitarize the disputed area, and as Khartoum stepped up air strikes in neighbouring South Kordofan.
Members of the Sudanese Armed Forces (SAF – northern army) exchanged fire with the Sudan People's Liberation Army at the Kiir, or Bahr al-Arab, river, the southern army's spokesman told AFP, without providing details of casualties.
Sudanese President Omar al-Bashir and his southern counterpart Salva Kiir had agreed on Monday, during crisis talks in Ethiopia, to a provisional deal to pull northern troops out of Abyei, after they overran the bitterly contested border district last month.
In adjacent South Kordofan, the UN expressed alarm at Sudan's intensified bombing campaign, which religious leaders and human rights activists said formed part of a government policy of ethnic cleansing, targeting the indigenous Nuba peoples who fought with the southern rebels during the 1983-2005 civil war.
After a wave of air strikes on Tuesday, allegedly targeting rebel positions in the Nuba Mountains, the United Nations peacekeeping mission in Sudan (UNMIS) said the situation in South Kordofan remained "extremely volatile and tense."
Earlier, a UN report said the Sudan Red Crecent Society had collected 25 dead bodies in the state capital Kadugli.
The World Food Programme said the lack of security was preventing it from providing emergency supplies to tens of thousands of people uprooted by the conflict, now thought to number more than 64,000.
"There is a growing sense of panic among some of the displaced populations who find themselves trapped by the ongoing violence and the ethnic fault lines," the UN humanitarian office reported.
Heavy fighting pitting the SAF and allied militiamen against fighters aligned to southern former rebel group the Sudan People's Liberation Army has raged across the state since 5 June.
On Tuesday, the SAF appeared to step up its air strikes on former rebel strongholds.
UNMIS said jet fighters dropped 11 bombs around the town of Kauda on Tuesday morning, as part of its ongoing bombing campaign that was causing "huge suffering" to the civilian population.
The SAF denied it was targeting civilians, saying it was battling a rebellion in South Kordofan, while a ruling party official at the information ministry insisted the Sudanese government treated all ethnic groups equally.
"Saying that the army is targeting the Nuba is false information (from the rebels), to show the world that they are suffering from marginalization," Rabie Abdel Ati told AFP.
A Sudanese human rights group reported this week that Antonov bombers had killed more than 65 people in air strikes in South Kordofan since the start of the fighting.
The Sudan Democracy First Group, in a six-page report, accused the SAF of pursuing a genocidal campaign against the Nuba in South Kordofan, supported by a feared civil war militia that now forms part of the northern army.
The accusations were echoed by opposition MPs in Khartoum.
"(The government) wants to pursue their Arab-Islamic state and anyone who opposes that will be eliminated. And the Nuba have the loudest voice in that, saying they are proud to be Nuba," Ahmed Saeed, a Nuba activist and MP for South Kordofan, told AFP.
Daniel Deng Bul, who as the Episcopal Archbishop of Sudan is the country's senior Anglican clergyman, also accused Khartoum of pursuing a policy of "ethnic cleansing" in South Kordofan, in a statement on Tuesday.
The UN refugee agency, meanwhile, has appealed to the Sudanese authorities to provide air and road access for humanitarian agencies to South Kordofan, where UN offices and warehouses have been looted.
Planes have been refused permission to land and roadblocks were hampering access by land, spokeswoman Melissa Fleming said.
Reports are also emerging of alleged extra-judicial killings carried out by the armed forces on Sudanese UN staff and on civilians, during house-to-house searches for suspected SPLA sympathisers.
US President Barack Obama said on Tuesday that there was no military solution to the conflict in South Kordofan, and urged the government of Sudan to halt its military operations immediately.
Also on Tuesday the vice president of the government of South Sudan, Riek Machar, met the US ambassador to the United Nations, Susan Rice, in New York, and warned that ethnic cleansing is looming in Southern Kordufan if no immediate action is taken.
A press release from Machar's office said the vice president also told Rice that the actions of the SAF in Abyei were a genocide in the making.
The United States has threatened to freeze the normalization of its ties with Sudan, warning the government it faced deeper international isolation if it did not halt the violence, which threatens to cast a pall over the run-up to southern independence next month.