Sudanese warplanes launched their first attack on a major South Sudanese town on Thursday, with five bombs dropped on the capital of the oil-producing Unity border state, Southern officials said. "They dropped bombs in Bentiu town - apparently they were aiming for a bridge," South Sudan's deputy information minister Atem Yaak Atem told AFP.
Bombs were dropped at dawn targeting a strategic bridge on the edge of Bentiu, which lies some 60 kilometres (40 miles) from the frontier, on the third straight day of violence.
The latest clashes, the worst since South Sudan won independence in July after one of Africa's longest civil wars, have brought the two former foes the closest to a return to outright war.
Parliaments in both countries on Wednesday urged their respective citizens to take up defences, but Atem said the South still did not want to go to war. "Our position is not to go to war except in self-defence," Atem said, adding that there were no reported casualties from Thursday's raid.
Atem said the targeted bridge was near a United Nations compound, slightly outside the town and on the road leading north to the frontline. "It doesn't take us by surprise, as all along they have been looking for excuses to go to war," he added.
"They never acknowledged the fact that South Sudan became independent... this (bombing) is to express their bitterness for the South going its own way."
Khartoum has vowed to react with "all means" against a three-pronged attack it said South Sudanese forces had launched against Sudan's South Kordofan state, including the Heglig oil field.
A statement on Khartoum's official SUNA news agency warned of "destruction" in South Sudan. "I think they want to disable communication and transport - they said they were going to destroy the South," Atem added.
"They have attacked other places like villages and oil installations and oil fields outside towns, but Bentiu is the first town to be hit."
The international community, including the African Union, United Nations and the United States, has called for restraint and voiced deep concern at the escalation of violence which saw South Sudan's army seize the Heglig oil region.
UN leader Ban Ki-moon urged South Sudan President Salva Kiir to meet with his rival from the north, while the US State Department has urged both sides to end "all hostilities".