The latest allegations indicated that continuing tensions between the two old civil war foes, which erupted into border fighting last month, could hamper international efforts to push them to resume negotiations on various outstanding disputes.

A South Sudan military spokesman, Kella Dual Kueth, told reporters Sudanese forces attacked South Sudanese territory in Bahr El Ghazal, Unity and Upper Nile states on Monday and Tuesday, using MiG jet fighters, Antonov bombers and ground shelling.

“Of course, automatically this is a violation (of the cease-fire). If we have a compromise and we are at peace and then I go and knife you in the back, what does that mean?” Kueth said.

In Khartoum, the Sudanese army spokesman did not answer repeated calls to comment on the allegations.

Addressing Sudanese parliamentarians yesterday, Sudanese Foreign Minister Ali Ahmed Karti said Khartoum would cooperate with a UN Security Council resolution which called on both sides to commit to an African Union (AU) peace roadmap.

“We ... will stick to the Security Council resolution ... Why be afraid of dealing with the Security Council resolution? Dealing with it positively gives a chance for our friends to defend us,” Karti told lawmakers.

Limited access to the remote border areas makes it difficult to verify often contradictory statements from both sides.

Simmering disputes over oil exports, border demarcation and citizenship, stemming from the South’s secession as an independent nation last year, bubbled over into direct clashes between the two rival armies in April.

As the conflict escalated, the United Nations condemned Sudanese air strikes on South Sudan’s territory and international pressure forced South Sudanese forces to withdraw from Heglig area which they had occupied.