Khartoum - Darfur rebels wounded in the latest fighting with Sudanese troops have gone to South Sudan for treatment, the army said on Tuesday, as Khartoum pushes Juba to end what it says is its backing for rebels.
The army and insurgents gave conflicting accounts of Monday's fighting, which came while Sudanese negotiators at fragile peace talks in Addis Ababa turned down South Sudan's proposal for settling oil fees and other critical issues by a United Nations-imposed deadline of 2 August.
Khartoum said security is a key priority and issues such as South Sudan's alleged backing of rebels need to be settled.
In a statement issued by the official SUNA news agency, Sudanese army spokesperson, Sawarmi Khaled Saad, said the government killed more than 50 fighters of the Justice and Equality Movement (JEM) and wounded a large number of others.
The fighting erupted just inside South Kordofan state near southeastern Darfur.
Saad said a "big number of vehicles were seen carrying the injured elements of the rebels for treatment in South Sudan."
Casualty claims are difficult to verify in the region, where access is restricted,.
In a statement late on Monday, the JEM made no mention of killed or wounded but said it had seized 36 military vehicles as it gained control of the Tabaldi oil field, as well as the Karkada area.
The rebels earlier Monday said they had seized control of a Sudanese military compound in the same region.
Sudan accuses South Sudan of working with the JEM and of backing insurgencies in South Kordofan and Blue Nile states.
The South denies supporting the rebels but suspected JEM fighters were seen alongside its troops during border fighting between Sudan and South Sudan in April.
On Sunday, the JEM again denied any presence in South Sudan, which accuses the north of backing insurgents in the South as well.
The UN has called on both sides to halt any such support, under a 2 May Security Council resolution which ordered a ceasefire along the border.
The resolution gave the two sides until 2 August to settle critical issues, including a dispute over oil, unresolved after the South's separation in July last year.
At African Union-led talks in the Ethiopian capital, Sudan on Monday rejected South Sudan's proposal of a higher oil transit fee and an $8.2 billion financial deal.
"We think security is a prerequisite," Mutrif Siddiq, a member of Khartoum's delegation, told reporters.