Sudanese warplanes carried out airstrikes on South Sudan on Monday, killing three people near a southern oil town, residents and military officials said, three days after South Sudan pulled out of a disputed oil field.
A Reuters reporter at the scene, outside the oil town of Bentiu, said he saw a fighter aircraft drop two bombs near a river bridge between Bentiu and the neighboring town of Rubkona.
"I can see market stalls burning in Rubkona in the background and the body of a small child burning," he said.
Mac Paul, deputy head of South Sudan's military intelligence, said two Sudanese MiG-29s had dropped four bombs in the area. "This is a serious escalation and violation of the territory of South Sudan. It's a clear provocation," Paul said.
Sudan's armed forces spokesperson was not immediately available to comment.
Weeks of border fighting between the two neighbors have brought the former civil war foes closer to a full-blown war than at any time since the South seceded in July.
Immediate tensions eased after the South said on Friday it would withdraw from Heglig, a disputed oil region that is central to Sudan's economy, but the South has accused Khartoum of bombing its territory since then.
On Sunday, Sudan denied the charges and said instead it had repulsed a "major" attack on a strategic border state town by rebels it says are backed by South Sudan.
The countries are still at loggerheads over the demarcation of their shared border, and other disputes have halted nearly all the oil production that underpins both economies.
South Sudan won its independence in a referendum that was promised in a 2005 peace accord that ended decades of civil war between Khartoum and the south. Religion, ethnicity and oil fueled that conflict, which killed about 2 million people.
Recent tensions between Sudan and South Sudan have been fueled by a dispute over how much the landlocked South should pay to export oil via Sudan.